What does apropos mean?
The definition of apropos
Ap”ro*pos`, a. & adv.
Etym: [F. 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.