Definition of time-depth in US English:

time-depth

noun

  • 1Literary a remote period of the past.

  • 2The extent to which something reflects or shows awareness of time.

  • 3Chiefly Anthropology, Archaeology, and Linguistics the distance in time between an (especially cultural or linguistic) event or epoch and the present, or between two events or epochs; (more generally) the span of time occupied by a particular culture, phenomenon, etc.

Origin

Late 19th century; earliest use found in Richard Proctor (1837–1888), astronomer and science writer.