Satin...a smooth opaque fabric with a glossy face and a matte (dull) back

Types of gown skirts:

Ball Gown
A very full, A-line skirt gown that starts at waist.
Fit-N-Flare
Skirt starts at mid thigh with a defined seam. The skirt then flares out moderately to extremely full.
Sheath
A very thin, straight, non-form fitting skirt with no flare
Mermaid
Skirt starts at knees with a defined seam and the skirt. Then skirt then has an extreme flare.
Trumpet
Skirt starts at waist and gently curves inward above knees without a defined seam.

Types of material:

Charmeuse...a very thin shiney satin

Chiffon...a light, sheer fabric
Organza...a smooth, slightly stiff fabric with a slight sheen

Lace Trim...a delicate fabric that is used for decorating the hem of a gown

Tulle...a soft, net-like material often starched for stiffness

Taffeta...a thin, crisp, lustrous fabric with a crisp texture

Shoulders/sleeveless--the shoulder part of the gown having a complete round armhole

Straps--spaghetti type strap no matter how wide, not a round armhole

Sleeves--are attached to the complete round armhole

Cap Sleeves--only on the top of the round armhole, stops half way or less down the armhole in the front and back

Bust--the curved seam in the front of the garment

Bodice--the top part of the gown with or without a waist seam

Skirt--the bottom of the gown below the waist

Empire Waist--the seam directly below the bust

Waist--most of the time it's a seam in the top portion of the gown below the bodice and above the hips

Hips--the part of the skirt directly below the waist seam 

Drop Waist--the waist seam of the gown lowered to the hips  

Hem--the bottom of the gown often touching the floor

Bustle--gathers up the train after the ceremony to keep it from dragging during the reception

Lining...a layer of material on the inner side of a gown

Parts of a Gown: