\Ap"ro*sos`\, a. & adv. [F. ? propos; ? (L. ad) + propos purpose, L. proposium plan, purpose, fr. proponere to propose. See {Propound}.] 1. Opportunely or opportune; seasonably or seasonable. A tale extremely apropos. --Pope. 2. By the way; to the purpose; suitably to the place or subject; -- a word used to introduce an incidental observation, suited to the occasion, though not strictly belonging to the narration.