1. Grammar. A word meaning literally ‘bent round’ applied to an accent-mark ˆ, ◠, or ˜, placed, originally in Greek, over long vowels having a particular accent or ‘tone’ (see accent n. 5); and thence transferred to other languages as a mark of length, of contraction, or of a particular variety of long vowel. Sometimes also applied to the tone, quantity, or quality indicated by this mark.The Greek περισπώμενος was used by Dionysius of Halicarnassus, 30 b.c. (περισπώμεναι λέξεις). According to Arcadius περὶ τόνων (c200 a.d.), probably copying Herodian (c150 a.d.), the sign and name are both attributed to Aristophanes of Byzantium (c264 b.c.). The original mark is said to have been ˆ a combination of ´ and ˋ, and hence called ὀξυβάρεια, for which however Aristophanes is said to have substituted ◠ to avoid confusion of ˆ with Lambda (Λ). This statement proves at least that the rounded form was the common one c200. In our oldest accented texts (7–9th centuries) both forms ˆ and ◠ exist, but the rounded form prevailed, and by later scribes was turned up with a flourish, thus ˜.The Latin grammarians of 2–3d centuries call the mark circumflexus, and generally agree as to its shape being ˆ (exc. Capella who used ◠); but it was not actually used in writing Latin till modern times, when sometimes introduced to indicate contraction as in amârunt for amaverunt, or in the ablative singular in -â. In recent times also it has been introduced in French to mark a long vowel, chiefly due to contraction, as in bête from beste. The circumflex used in normalized printing of Old High German, and other Teutonic languages, to express long quantity, originated in an acute accent ´ (as in Old English), which being thus made ?, has been confounded with the Romanized form of the circumflex.In modern English use the mark has no definite value, but is variously used by orthoepists or phonetists to mark long quantity, ‘broad’ quality, or the like.

2. Bent or bending round; †circuitous.

3. Anatomy. Applied to certain structures of curved or winding form, or which bend round others; as the circumflex arteries of the arm (anterior and posterior c. a.), of the thigh (internal and external), of the knee; the circumflex iliac artery and vein; the circumflex nerve of the arm; the circumflex muscle of the palate, or tensor palati.

†2. Bending round, winding, curve, a curved line.

3. A curved line, (or {, bracketing two or more lines of writing. ? Obsolete.