Diaper:  Absorbent fabric, usually cotton, wrapped, folded or sewn to fit a baby like underpants to absorb excrement.

Diaper Cover/Wrap:  A waterproof or water-resistant pant that is worn over a cloth diaper to form a moisture barrier between the diaper and the clothing. Many diaper wrap styles also hold the diaper in place without the use of pins or other fasteners. Sometimes, a knitted wool diaper cover is called a soaker.

Diaper Doubler/Booster:  An absorbent fabric sewn or folded, similar to a long sanitary napkin, and placed down the center of a cloth diaper for added absorbency.

Liner:  This is optional. A thin layer of material laid in the diaper, the purpose being that when the baby messes, the liner can be rinsed or disposed of more easily than the whole diaper. A liner can be washable, flushable, or disposable.

All-In-One:  The absorbent fabric diaper and the waterproof cover sewn together making a single-unit cloth diaper/diaper cover combo.

Inner:  The layer of a cloth diaper that is against the baby's skin.

Outer:  The layer of a cloth diaper that you see after the diaper is fastened onto the baby.

Inner Pad/Soaker:  The thicker, absorbent, center part of a cloth diaper, usually, but not always, between the inner and outer layers. Sometimes, a knitted wool diaper cover is also called a soaker.

Wings or Tabs:  The back part of a diaper that wraps around to the front when fastening it on a baby.