/ Dictionary / Index C control unit: Meaning and Definition of Find definitions for: control' u"nit Pronunciation: [key] — Computers. Computers. the part of a CPU that interprets the instructions in programs and directs the operation of the entire system. controller (def. 5). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. control tower controversial Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language