I am taking this from The Diaper Jungle because it's such a great desciption of them. I thought they might help out any moms on here trying to understand cloth diapers.

http://www.diaperjungle.com/cloth-diaper-terminology.html

Cloth Diaper Terminology

AIOs, pockets, fitteds, doublers, soakers...it can get a little confusing for a cloth newbie. Let us help you sort it all out. On this page we provide definitions for all the major cloth diapering products.


 AIO - All-In-One - AIOs are fitted diapers that have a waterproof outer layer. This layer usually consists of fabric that has a PUL (PolyUrethane Laminate) backing, polar fleece such as Windpro, or wool. These are the closest in similarity to disposable diapers since they are a one-piece diapering system. The absorbent soaker material is often sewn into the diaper; it may also be detachable.

AI2 - All-In-Two - AI2s are very similar to AIOs with the exception that the absorbent soaker material is not attached to the diaper in any way. The soaker is usually a second, separate piece that must be used in conjunction with the diaper. The drying time for these diapers is shorter than the traditional AIO. 

 
Contour Diapers - Contours are hourglass shaped diapers with no elastic in the legs or back. They must be held together with a SNAPPI® Diaper Fastener, pins, or a diaper cover. These diapers are not waterproof, so a cover will be needed.


 Diaper Covers - Covers come in many styles and shapes, but their function is to provide a waterproof outer layer for non-waterproof diapers (all except AIOs). They are often fitted with elastic and fasten with snaps or Velcro. Some covers pull-up, like underpants. Diaper covers are usually made from polyester, Polyurethane laminates (PUL), waterproof nylon, fleece or wool.

DSQ ~ This stands for Diaper Service Quality. Diaper services use only the highest quality materials because their diapers must stand up to a lot of use and a lot of laundering. DSQ is usually used in reference to high quality pre-fold diapers.

 Doublers – Doublers are pad-like absorbent soakers that can be added to a diaper to increase absorbency. They are especially useful during times when you know extra protection is needed, perhaps at night time.


Flats - These one-layer diapers, generally made out of 100% cotton gauze, are the most "old-fashioned" choice. They dry quickly and fit a large range of sizes. Folding and pinning are required. 

 Fitted Diapers - Fitted diapers closely resemble disposable diapers. They are contoured and fitted with elastic around the legs and back. They fasten with Velcro or snaps, and a waterproof cover must be worn over them. They are the next step up from flat pre-fold diapers and much easier to use.

Hook & Loop - These are Velcro-like closures. Since the Velcro brand is not very soft, many diaper makers use Aplix or Touchtape brand hook and loop.

Liners - Liners are thin layers of cloth or paper that are placed inside the diaper to aid in the cleaning of solid waste. In the case of paper liners, the solid waste collected on the liner can be removed from the soiled diaper and either thrown away or flushed. Cloth liners must be washed, but aid in laundering. They also help protect the actual diaper from staining.

Longies - These are also called soaker pants or sweater pants. Longies are wool soakers that have longer legs to form pants. They are great for winter time.

 Pre-folds - Pre-fold diapers are rectangular shaped diapers that must be folded into the shape of a diaper. They are similar to flats, but have multiple layers with more layering in the middle. They often have 2-4 layers of absorbent material on either side and 6-8 layers in the middle. The amount of layers varies according to the size you choose, generally ranging from preemie to toddler. You may see a pre-fold described as being 4x8x4. This describes how many layers there are in the outer and inner sections: 4 layers in both outer sections and 8 layers in the inner or middle section. Pre-folds are usually the cheapest type of cloth diapers available. They must be used in conjunction with a cover. 


 Pocket Diapers - Pocket diapers are like AIOs orAI2s. They have an outer layer of a waterproof material and an inner layer of a stay dry material, like microfleece or suedecloth. They close with Velcro or snaps. They have a pocket opening that allows for the absorbent material to be stuffed in the pocket during use and then removed for laundering. The absorbent material for stuffing can be an insert that comes with the diaper or a pre-fold or doubler. Some moms use terry wash cloths. Pocket diapers are a popular choice among cloth diapering moms because you can customize the amount of absorbent material. 

 Snappi® - A plastic mechanism that fastens a cloth diapers. These are often used instead of diaper pins.



Soaker Pants - See Longies

Soakers - The term soaker can be applied two ways. It often refers to the absorbent middle part of the diaper that absorbs the moisture when a baby wets. Soakers may be sewn inside the diaper, partially sewn to form a flap, snapped in inside the diaper, or simply laid inside the diaper. The term soaker is also used in reference to wool diaper covers. 

Wool In One (WIO) - This is a All-In-One (AIO) but made with wool outer fabric.
 

http://www.diaperjungle.com/cloth-diaper-lingo.html

Cloth Diaper Lingo and Abbreviations

As you you enter the world of cloth diapering via online message boards and discussion groups, you might get a little lost. Cloth diapers tend to have their own lingo when discussed among friends...so we have compiled a list of popular words and abbreviations related to cloth diapering that may help you figure out what is being said! Some of these are not specific to cloth diapering but seem to come up frequently in online conversations and are rather universal in nature. Enjoy!


AIO - All in One diaper

AI2 - All in Two diaper

AP - Attachment parenting

BF - Breastfeed

BTDT - Been there done that

BTW - By the way

CD - cloth diaper

Crunchy - Natural lifestyle

CPF - Chinese prefold

DSQ - Diaper service quality

EC - Excellent condition

F&C - Free & Clear (used referring to detergents)

FLer - Front loader washing machine

FS - For sale

FSOT - For sale or trade

FYI - For your information

Hyena - A term for hard to get, popular diapers that are stalked by diaper hungry moms

IPF - Indian Prefold

IMO - In my opinion

ISO - In search of

ITA - I totally agree

KWIM - Know what I mean

LMK - Let me know

LO - Little one

LOL - Laugh out loud

NAK - Nursing at Keyboard

PUL - polyurethane laminate, a material used to make diaper covers/wraps

ROFLOL - rolling on the floor, laughing out loud

SAHM - stay-at-home mom

TLer - Top loader washing machine

WAHM - work-at-home mom



Diaper Brands Commonly Referred To With Abbreviations:

BG - bumGenius

FM - Fluffy Mail

FMBG - Full Moon Baby Gear

FB - Fuzzi Bunz

HH - Happy Heiny's

LC - Little Caboose

ME - Motherease

GAD - Green Acre Designs

SEZ - Snap E-Z

http://www.diaperjungle.com/cloth-diaper-types.html

The 4 Major Cloth Diaper Types - Prefolds, AIOs and AI2s, Pockets, & Fitteds

Confused about the different diaper types out there? This chart will help you sort it all out.

Prefolds	AIOs/AI2s	Pocket Diapers	Fitted Diapers
Requires a wrap or a cover	Does not requires a wrap or a cover - this feature is built in.	Does not requires a wrap or a cover - this feature is built in.	Requires a wrap or a cover
May require a fastener such as pins or a snappi	Usually fastens with snaps or hook and loop (velcro)	Usually fastens with snaps or hook and loop (velcro)	Usually fastens with snaps or hook and loop (velcro), sometimes a snappi or pins may be used.
Usually made of cotton, gauze, Birdseye flannel, hemp, or velour.	Outer layer is waterproof...usually made with PUL, Procare, fleece, or wool.	Outer layer is waterproof...usually made with PUL, Procare, fleece, or wool.	Outer and inner layers are not waterproof and may consist of many different fabrics types.
	A doubler will increase absorbency. A separate stuffer or doubler lays inside an AI2.	Requires and absorbent stuffer material to be placed in the pocket before use.	A doubler will increase absorbency.
	Usually has elastic and legs and back area.	Usually has elastic and legs and back area.	Usually has elastic and legs and back area.

http://www.diaperjungle.com/aio-cloth-diapers.html

AIO or All In One Cloth Diapers and AI2 Cloth Diapers

 An AIO, or All-In-One, is exactly what it sounds like. What you get is what you need. It is a type of diaper that functions completely on its own without the need for extra accessories. It does not require separate soaker material to absorb nor a separate diaper cover to contain leaks. All of the features are neatly packaged into one diaper. Many parents find this type of diaper to be the height of convenience since all they need is in one place. It also saves on space when traveling.

Advantages of AIO Cloth Diapers:

• Functions like a disposable, except you don't throw it away!
   
• No separate cover required
   
• No separate soaker or doubler required
   
• Easy to use
   
• Available in lots of cute colors and prints
   
• Perferred by childcare givers
   

Disadvantages of AIO Cloth Diapers:

• Longer drying times
   
• Harder to clean effectively
   

If you like the sound of an AIO but worry about the longer drying and cleaning times, you may want to try an AI2. These diapers are All in Ones that allow for the removal of the inner soaker material, the part that absorbs. This makes cleaning and drying much faster. When the two separate parts are paired, they form one diaper.

Advantages of AI2 Cloth Diapers:

• No separate cover required
   
• Great for transitioning from disposables to cloth - easy to use
   
• Available in lots of cute colors and prints
   
• You can always get a new soaker or doubler if the original needs to be replaced
   

Disadvantages of AI2 Cloth Diapers:

• Keeping soakers or doublers together with the rest of the diaper
   
• Usually more expensive than other cloth diapering methods
   

Examples of All in One (AIO) Cloth Diapers:

• bumGenius AIO
   
• Jam Tots BerryPlush
   
• Bumkins
   
• Swaddlebees AIO
   
• Very Baby

http://www.diaperjungle.com/fitted-cloth-diapers.html

Fitted Cloth Diapers

Fitted cloth diapers are the next step up in the evolution of the cloth diaper, after the simple flat diapers or prefold diapers that were the norm many years ago. Fitted diapers are exactly what they sound like. Instead of the flat and shapeless diapers our parents may have used, fitted diapers are fitted and snug, usually with elastic gatherings in the legs and waist. This makes them a perfect fit for any baby. They usually have closures of some sort as well, either hook and loop (Velcro) or snaps.

Fitted diapers are not waterproof so you do need a diaper cover to put over them. But they are very easy to put on a baby and very easy to put under a cover without uncomfortable bunching. Some fitted diapers have also been known to contain a pocket for stuffing

Fitted diapers come in a variety of materials. Some of the most popular choices are cotton knits, flannel, hemp, terry cloth, sherpa, bamboo, and velour.

Advantages of Fitted Diapers:

• Fitted and snug for a good fit on baby and under diaper covers
   
• Can be washed at high temperatures, separate from covers
   
• Easy to clean
   
• Can be very trim for day use or bulkier for nighttime use...your choice.
   
• Available in lots of cute colors and prints
   

Disadvantages of Fitted Diapers:

• A cover is required to make the diaper function
   
• Not as convenient as an
   
• Can be hard to wash and may have smell problems if there are too many layers
   

Examples of Fitted Diapers:

• Kissaluvs
   
• Happy Hempy
   
• Little Beetles
   

http://www.diaperjungle.com/pocket-diapers.html

Pocket Diapers

Pocket diapers are exactly what they sound like. They are cloth diapers that have a pocket. Most generally they have two layers, an outer layer and an inner layer, with a hole or pocket that separate the two at one point, forming an opening for the absorbent material to be inserted. The absorbent material that is inserted into the pocket is what absorbs the moisture when baby relieves himself. It can be removed later for more effective cleaning. Many moms believe that pocket diapers are the most innovative invention in diapering ever.

Pocket diapers can be two piece diapering systems with a waterproof outer layer that requires only a stuffer. They can also be a three piece diapering system with a non-waterproof outer layer that will require the use of a diaper cover.

Advantages of Pocket Diapers:

• You decide what to "stuff" the pocket with...so you can find the right absorbency level
   
• Easy to clean because they "come apart"
   
• Can be very trim if absorbent stuffing is not bulky
   
• Available in lots of cute colors and prints
   

Disadvantages of Pocket Diapers

• A separate stuffer is required to make the diaper function
   
• Can be bulky if to much stuffin' in inserted
   

Examples of Pocket Diapers:

• Fuzzibunz
   
• Wonderoos
   
• Happy Heinys
   

http://www.diaperjungle.com/prefold-cloth-diapers.html

Flat and Prefold Cloth Diapers

Flat cloth diapers are the classic cotton square which is folded to fit baby, and secured with diaper pins or a Snappi.

A variation of the flat diaper is the Prefold, which includes extra layering in the center.


Flat and prefold diapers are the least expensive choice in cloth diapers, costing in the area of $15-$20 per dozen. These diapers require waterproof outer covers, so they are a three piece diapering system (diaper, cover, closure for diaper). Typically, these diapers are closed with either diaper pins or a Snappi. However, another option is to simply lay them in a wrap style cover and forgo the additional closure type.

Most of these diapers are made from birdseye or other gauzy fabrics. Some are made from velour or hemp. They are very absorbent, easy to clean, and quick to dry. Still widely used today, flat and prefold diapers are a very economical and simple choice for cloth diapering. But these cloth diapers have other uses as well. Fans of other diapering types often use flat or prefold diapers for doublers or pocket stuffers.

For a little fun with prefold or flat diapers, look at the many dyed or embroidered options available on the market.


Advantages of Flat and/or Prefold Diapers:

• Absorbent
   
• Very economical
   
• Easy to launder and fast to dry
   
• Can be used as diapers, doublers, pocket stuffers, burp cloths, or even cleaning rags.
   
• Available in lots of dyed colors, and can be embroidered very easily.
   

Disadvantages of Flat and or Prefold Diapers:

• A cover is required to make the diaper function
   
• Must take the time to fold
   
• Not as convenient as an AIO
   
• Hard to use on squirmy babies
   
• Pins and/or a Snappi can be hard to use
   
• Runny messes are harder to contain with these diapers