Vic"i*nal [L. vicinalis: cf. F. vicinal.]
Near; vicine.
T. Warton.
<-- (Organic Chem.) Having the substituted groups on the same carbon atom. -->
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.
© Webster 1913.