—adj.
1 to the point or purpose; appropriate (his comment was apropos).
2 colloq. (often foll. by of) in respect of; concerning (apropos the meeting; apropos of the talk).
—adv.
1 appropriately (spoke apropos).
2 (absol.) by the way; incidentally ({{}}apropos, she's not going).
Etymology: F agrave propos f. agrave to + propos PURPOSE
Useful english dictionary. 2012.