Definify.com
Webster 1913 Edition
Vicinal
Vic′i-nal
(?; 277)
, Adj.
[L.
vicinalis
: cf. F. vicinal
.] 1.
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.