|Look up simultaneity, simultaneous, or simultaneously in Wiktionary, the free dictionary.|
Simultaneity is the relation between two events assumed to be happening at the same time in a frame of reference.
Simultaneity may also refer to:
- Relativity of simultaneity, a concept in special relativity.
- Simultaneity (music), more than one complete musical texture occurring at the same time, rather than in succession
- Simultaneity, a concept in Endogeneity