/ Thesaurus / R Synonyms of root cap Find synonyms for: Noun1. root cap, plant organusage: thimble-shaped mass of cells covering and protecting the growing tip of a rootWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: abominable Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language