disjunction

Short definition from Wiktionary

Noun

1. 1
   The act of disjoining; disunion, separation.
2. 2
   The state of being disjoined, contrasting, or opposing.
3. 3
   The proposition resulting from the combination of two or more propositions using the or operator.
4. 4
   A logical operator that results in “true” when any of its operands are true.
5. 5
   During meiosis, the separation of chromosomes (homologous in meiosis I, and sister chromatids in meiosis II).