ALTERNATION
alternation
(noun) successive change from one thing or state to another and back again; “a trill is a rapid alternation between the two notes”
Source: WordNet® 3.1
Etymology
Noun
alternation (countable and uncountable, plural alternations)
The reciprocal succession of (normally two) things in time or place; the act of following and being followed by turns; alternate succession, performance, or occurrence
(religion) The response of the congregation speaking alternately with the minister.
(linguistics) Ablaut.
(linguistics) A pattern by which more than one construct is possible, as with "Alice cooked Bob dinner" and "Alice cooked dinner for Bob".
(logic) The "inclusive or" truth function.
(mathematics) A sequence that alternates between positive and negative values; sometimes incorrectly used to mean permutation.
(computing) A construct in a regular expression that can match any of several specified subexpressions.
(geometry) A type of partial truncation of a polygon, polyhedron or tiling in which alternate vertices are removed.
Source: Wiktionary
Al`ter*na"tion, n. Etym: [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.)
Definition: Permutation.
3. The response of the congregation speaking alternately with the
minister. Mason. Alternation of generation. See under Generation.
Source: Webster’s Unabridged Dictionary 1913 Edition