n. 交互, 轮流, 间隔

[计] 交替工作

[医] 交替, 更替, 更迭, 互生(植物)

[ noun ]
successive change from one thing or state to another and back again
<noun.act>
a trill is a rapid alternation between the two notes

Alternation \Al`ter*na"tion\, n. [L. alternatio: cf. F.
alternation.]
1. The reciprocal succession of things in time or place; the
act of following and being followed by turns; alternate
succession, performance, or occurrence; as, the
alternation of day and night, cold and heat, summer and
winter, hope and fear.

2. (Math.) Permutation.

3. The response of the congregation speaking alternately with
the minister. --Mason.

{Alternation of generation}. See under {Generation}.

Permutation \Per`mu*ta"tion\, n. [L. permutatio: cf. F.
permutation. See {Permute}.]
1. The act of permuting; exchange of the thing for another;
mutual transference; interchange.

The violent convulsions and permutations that have
been made in property. --Burke.

2. (Math.)
(a) The arrangement of any determinate number of things,
as units, objects, letters, etc., in all possible
orders, one after the other; -- called also
{alternation}. Cf. {Combination}, n., 4.
(b) Any one of such possible arrangements.

3. (Law) Barter; exchange.

{Permutation lock}, a lock in which the parts can be
transposed or shifted, so as to require different
arrangements of the tumblers on different occasions of
unlocking.