/ Dictionary / Index A aplacental: Meaning and Definition of Find definitions for: a•pla•cen•tal Pronunciation: (ā"plu-sen'tl, ap"lu-), [key] — adj. Zool. having or forming no placenta, as the marsupials and monotremes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: aplacental (Thesaurus) APL aplacophoran Related Content Daily Word Quiz: fervor Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language