Emollient

Emollients soften skin (and moisturisers add moisture). They are used to correct dryness and scaling of the skin.

The terms 'moisturiser' (to add moisture) and 'emollient' (to soften) are interchangeable as they describe different effects of these agents on the skin. Basically they have two actions:

Occlusives

which provide a layer of oil on the surface of the skin to slow water loss and thus increase the moisture content of the stratum corneum.

Humectants

which are substances introduced into the stratum[?] corneum to increase its water holding capacity.

Some moisturisers[?] contain both occlusives and humectants.

http://www.dermnetnz.org/dna.emoll/emoll.html