Definitions for: Vicinal

[adj] belonging to or limited to a vicinity

Webster (1913) Definition: Vic"i*nal (?; 277), a. [L. vicinalis: cf. F. vicinal.]
Near; vicine. --T. Warton.

Vicinal planes (Min.), subordinate planes on a crystal,
which are very near to the fundamental planes in angles,
and sometimes take their place. They have in general very
complex symbols.