English
achronal
From a- + chronal.
Proto-Indo-European *uds- ‘up, out’
Proto-Germanic *uz- ‘out-’
Proto-West Germanic *uʀ- ‘up, out, over’
English a-
Today it means
adj Describing a set of points in a spacetime, no two of which have timelike separation
Language periods are conventional ranges, not dates for this word.
Etymograph / achronal