/ Thesaurus / P Synonyms of polycillin Find synonyms for: Noun1. ampicillin, Principen, Polycillin, SK-Ampicillin, penicillinusage: semisynthetic penicillin (trade names Principen and Polycillin and SK-Ampicillin)WordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: reticent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language