Alan Shepard alans·he·pard uncommon noun 1. astronaut who made the first United States'' suborbital rocket-powered flight in 1961 (1923-1998) SynonymsShepardAlan ShepardAlan Bartlett Shepard Jr. Related words Broader terms astronaut WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
