Circumflex is a diacritic mark used in written French and Esperanto.

In French:

â ê î ô û

In Esperanto:

ĉ ĝ ĥ ĵ ŝ

In French the circumflex is largely redundant. It marks the former presence of the letter s in the spelling of the word. For example: hôpital, forêt.

English uses the circumflex on loan words, for example rôle.

In Esperanto it indicates a completely different consonant from the unaccented form, and is considered a separate letter for purposes of collation. See Esperanto orthography.