/ Dictionary / Index H HTLV-1: Meaning and Definition of Find definitions for: HTLV-1 Pronunciation: [key] human T-cell lymphotropic virus type 1: a type of retrovirus that causes a rare form of leukemia, primarily occurring in southern Japan and the Caribbean islands. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: htlv-1 (Thesaurus) HTLV HTLV-2 Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language