Pronunciation: ˌ f ō -t ō - ˌ ek- ˌ s ī - ' t ā -sh ə n, - ˌ ek-s ə -
Function: noun
Date: 1918
: the process of exciting the atoms or molecules of a substance by the absorption of radiant energy
– pho · to · ex · cit · ed \ -ik- ' s ī -t ə d, -ek- \ adjective