- existing, occurring, or operating at the same time; concurrent: simultaneous movements; simultaneous translation.
Origin of simultaneous
SynonymsSee more synonyms for simultaneous on Thesaurus.com
Examples from the Web for simultaneity
Twins they were in simultaneity of birth, but not in likeness of growth.A Century of Science and Other Essays
We have not a direct intuition of simultaneity, nor of the equality of two durations.Major Prophets of To-Day
Edwin E. Slosson
This simultaneity and concurrency are central tenets of imposing Shock and Awe.Shock and Awe
Harlan K. Ullman
One may not appear twice in simultaneity upon the Time-scroll.
He was interested by the celerity, the simultaneity of his impressions, his reflections.Literature and Life
William Dean Howells
- occurring, existing, or operating at the same time; concurrent
- chess a display in which one player plays a number of opponents at once, walking from board to boardSometimes shortened to: simul
Word Origin and History for simultaneity
1650s, from Medieval Latin simultaneus, perhaps from simultim "at the same time," extended from Latin simul "at the same time" (see similar (adj.)), or from simul with ending abstracted from Late Latin spontaneus, where the -t- is organic. Related: Simultaneously.