epicyclic gear epi·cyc·lic·gear uncommon noun 1. an outer gear that revolves about a central sun gear of an epicyclic train Synonymsplanetary gearepicyclic gearplanet wheelplanet gear Related words Word family epicyclic gear train Broader terms gear Parts epicyclic train WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
