/ Dictionary / Index P Pentothal: Meaning and Definition of Find definitions for: Pen•to•thal Pronunciation: (pen'tu-thôl"), [key] — Pharm., Trademark. Pharm.,Trademark. a brand of thiopental sodium. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pentothal (Thesaurus) pentose nucleic acid pentoxide Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language