Crossword Clue:

a hypothetical unit of time

AnswerCrossword Clue
IDICOf a hypothetical unit of living matter
EPOCHA unit of geological time
ANOSpanish unit of time with a tilde
SECShort for a time unit.
SATURDAYTime unit named for a Roman god.
FOURTHDIMENSIONHypothetical unit in theory of relativity