a combining form with the meanings âheight,â âtip end,â âextremities of the body,â used in the formation of compound words: acrophobia. Also, especially before a vowel, acr-. Origin of acro-. < Greek, combining form of Ã¡kros topmost, highest; akin to Latin Äcer sharp.
â¢ CANTUS FIRMUS (noun) The noun CANTUS FIRMUS has 1 sense: 1. a melody used as the basis for a polyphonic composition. Familiarity information: CANTUS FIRMUS used as a noun is very rare. Dictionary entry details.
Sagittal keel. The Sagittal keel (torus) is a thickening of bone on part or all of the midline of the frontal bone, or parietal bones where they meet along the sagittal suture, or on both bones. Sagittal keels differ from sagittal crests, which are found in some earlier hominins (notably the genus Paranthropus) and in a range of other mammals.