Positioned at rest in respect to another, be it side-to-side, front-to-front, back-to-back, or even three-dimensionally: in apposition.
Strikingly appropriate or relevant; well suited to the circumstance or in relation to something.
Related, homologous.
That which is apposite; something suitable.
of, relating to, or located on the right
in the direction or orientation to the right-hand rule (a right-hand thread)
designed for use by the right hand