A plane showing relationships in time; a level of existence defined in terms of time; (Geology) a notional plane separating strata of different geological periods or joining fossils of the same age.
Origin
Late 19th century.
Definition of time plane in US English:
time plane
noun
A plane showing relationships in time; a level of existence defined in terms of time; (Geology) a notional plane separating strata of different geological periods or joining fossils of the same age.