An Etymological Dictionary of Astronomy and Astrophysics

The precise time at which the gamma burst photons hit a
detector. Measuring the time difference between the arrival time of the photons at different telescopes separated by known distances permits to determine the burst direction.

Etymology (EN): Arrival, n. from arrive + → -al. Arrive, from O.Fr. ariver “to come to land,” from V.L. *arripare “to touch the shore,” from L. ad ripam “to the shore,” from → ad “to” + ripa “shore;” → time.

Etymology (PE): Zamân, → time; raseš n. from rasidan “to arrive,” Mid.Pers. rasitan, O.Pers./Av. rasa- present stem of ar- “to move, go or come toward,” cf. Skt. ar-, rcchati.