Origin: 1400–50; late ME
expanden < L
expandere to spread out, equiv. to
ex- ex- 1 +
pandere to extend, stretch
Related forms: ex⋅pand⋅a⋅ble, ex⋅pand⋅i⋅ble, adjective
ex⋅pand⋅a⋅bil⋅i⋅ty, ex⋅pand⋅i⋅bil⋅i⋅ty, noun
Synonyms:1. extend, swell, enlarge.
See increase. Expand, dilate, distend, inflate imply becoming larger and filling more space.
To expand is to spread out, usually in every direction:
to expand one's chest. To dilate is esp. to increase the width or circumference, and applies to space enclosed within confines or to hollow bodies:
to dilate the pupils of the eyes. To distend is to stretch, often beyond the point of natural expansion:
to distend an artery. To inflate is to blow out or swell a hollow body with air or gas:
to inflate a balloon. 
[ik-spand] 