Webster's Dictionary 
(1): ( n.) Space through which anything is expanded; also, pure space.
(2): ( n.) Enlargement or extension of business transactions; esp., increase of the circulation of bank notes.
(3): ( n.) That which is expanded; expanse; extend surface; as, the expansion of a sheet or of a lake; the expansion was formed of metal.
(4): ( n.) The act of expanding or spreading out; the condition of being expanded; dilation; enlargement.
(5): ( n.) The operation of steam in a cylinder after its communication with the boiler has been cut off, by which it continues to exert pressure upon the moving piston.
(6): ( n.) The enlargement of the ship mathematically from a model or drawing to the full or building size, in the process of construction.
(7): ( n.) The developed result of an indicated operation; as, the expansion of (a + b)2 is a2 + 2ab + b2.
King James Dictionary 
1. The state of being expanded the enlargement of surface or bulk dilatation. We apply expansion to surface, as the expansion of a sheet or of a lake, and to bulk, as the expansion of fluids or metals by heat but not to a line or length without breadth. 2. Extent space to which any thing is enlarged also, pure space or distance between remote bodies. 3. Enlargement as the expansion of the heart or affections.