【医】 选择性亲[和]力

Elective \E*lect"ive\, a. [Cf. F. ['e]lectif.]
1. Exerting the power of choice; selecting; as, an elective
act.

2. Pertaining to, or consisting in, choice, or right of
choosing; electoral.

The independent use of their elective franchise.
--Bancroft.

3. Bestowed or passing by election; as, an elective office.

Kings of Rome were at first elective; . . . for such
are the conditions of an elective kingdom. --Dryden.

4. Dependent on choice; that can be refused; as, an elective
college course. Opposite of {required} or {mandatory}.
[1913 Webster +PJC]

{Elective affinity} or {Elective attraction} (Chem.), a
tendency to unite with certain things; chemism.