apposite

Short definition from Wiktionary

Adjective

1. 1
   Strikingly appropriate or relevant; well suited to the circumstance or in relation to something.
2. 2
   Positioned at rest in respect to another, be it side-to-side, front-to-front, back-to-back, or even three-dimensionally: in apposition.
3. 3
   Related, homologous.

Noun

1. 1
   That which is apposite; something suitable.