Alternation

Noun

1. 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

   "the alternation of day and night"

2. The response of the congregation speaking alternately with the minister.
3. Ablaut.
4. A pattern by which more than one construct is possible, as with "Alice cooked Bob dinner" and "Alice cooked dinner for Bob".

   "dative alternation; locative alternation"

5. The "inclusive or" truth function.