/ Dictionary / Index M mastigium: Meaning and Definition of Find definitions for: mas•tig•i•um Pronunciation: (ma-stij'ē-um), [key] — pl. mas•tig•i•a an extensible, lashlike, anal organ in certain caterpillars. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mastiff bat Mastigophora Related Content Daily Word Quiz: penury Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language