n.
Pronunciation: ' fäz- ˌ j ē n
Function: noun
Etymology: Greek ph ō s light + -gen ē s born, produced ― more at FANCY , -GEN ; from its originally having been obtained by the action of sunlight
Date: 1812
: a colorless gas COCl 2 of unpleasant odor that is a severe respiratory irritant that has been used in chemical warfare