An Etymological Dictionary of Astronomy and Astrophysics

General: A meeting, especially one that is unplanned, unexpected, or brief. An often violent meeting; a clash.
Coming across of two bodies (as two stars in a cluster) which results in the deviation from
original directions of motion. → close encounter; → strong encounter; → weak encounter.

Etymology (EN): From O.Fr. encountrer “confront,” from encontre “against, counter to,” from L.L. incontra “in front of,” from L. in- “in” + contra “against.”

Etymology (PE): Ruyâruyi “being face to face,” from ru, ruy “face, countenance,” variant rox (Mid.Pers. rôy, rôdh “face,” Av. raoδa- “growth,” in plural “appearance,” from raod- “to grow, sprout, shoot,” cf. Skt. róha- “rising, height”) + euphonic interfix -â- + ruy + noun suffix -i.