terminus post quem
Terminus post quem ("limit after which", sometimes abbreviated to TPQ) and terminus ante quem ("limit before which", abbreviated to TAQ) specify the known limits of dating for events or items.A terminus post quem is the earliest date the event may have happened or the item was in existence, and a terminus ante quem is the latest. An event may well have both a terminus post quem and a terminus ante quem, in which case the limits of the possible range of dates are known at both ends, but many events have just one or the other. Similarly, terminus ad quem ("limit to which") is the latest possible date of a non-punctual event (period, era, etc. ), while terminus a quo ("limit from which") is the earliest. The concepts are similar to those of upper and lower bounds in mathematics. These terms are often used in archaeological and historical studies, such as dating layers in excavated sites, coins, historical events, authors, inscriptions or texts where the exact dates may not be known or may be in dispute.
earliest date possible for something
Latin phrase