| Definition -
The form of a verb that shows the absolute location of an event or action in time, e.g.
David walks to school (present tense)
and David walked to school (past tense).
As opposed to aspect, which shows how an event or action is spread over time, e.g. whether it is instantaneous (swat a fly) or habitual (He swats flies every Friday).
Etymology - The word derives via the Old French tens, time (from the Latin tempus, time).
Oxford English Dictionary - Its first citation is from 1388:
"A participl of a present tens … may be resoluid into a verbe of the same tens, and a coniunccion copulatif."
(Wyclif Prol. xv. 57 )