An Etymological Dictionary of Astronomy and Astrophysics

In the course of, in the time of, throughout the continuance of.

Etymology (EN): M.E. Duryng, durand, pr.p. of duren “to last, endure, continue, be or exist,” from O.Fr. durer, from L. durare “to harden,” from durus “hard;” PIE root *deru- “be firm, solid, steadfast.”

Etymology (PE): Tarpây, literally “lasting over time,” from tar- “through, across, over time,” variant tarâ-, → trans-, + pây present stem and agent noun of pâyidan, → last (v.).