D defs.my
Entry 2 senses Webster, 1913

Apropos

/(ăp"rō̇*pō`)/ · Ap·ro·pos · IPA /ˌæp.ɹəˈpoʊ/
01 a. & adv. Opportunely or opportune; seasonably or seasonable.
  1. 1.
    Opportunely or opportune; seasonably or seasonable.
    “A tale extremely apropos.” Pope.
  2. 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.