teimjau fu'ivla

x1 (nu, or time-/date-stamp) is the event/moment in time when the elapsed time/duration from the death or end of x2 (entity/object, or process) is equal to the temporal measure of its lifetime (elapsed time from its birth/beginning until its death/end), in frame of reference x3.

This is essentially a particular type of te teirmijyfau.

In notes:

The elapsed time/duration between x1 (nu, or time-/date-stamp) and x2 (nu, or time-/date-stamp) is equal to the elapsed time/duration between x1 and x3 (nu, or time-/date-stamp), such that x2 occurred no later than x3 (thus, x1 is also a temporal midpoint between them), in frame of reference x4.