A word used as the title of a section, particularly in a dictionary, encyclopedia, or thesaurus. / (grammar) Any word which may be modified by an adjunct.

The upper portion of a page (or other) layout. / Text, or other visual information, used to mark off a quantity of text, often titling or summarizing it.

(sports, transitive) To strike (a ball) with one's head.

Movement ahead or forward. / (nautical) Forward motion, or its rate.

Determined to do as one pleases, and not as others want.

(chiefly UK) A male school principal.

(idiomatic) To progress; to move forward.

(electronics) The ability of an amplifier to handle strong signals (or loud sounds) free from distortion.

The vertical clearance above someone's head, as in a tunnel, doorway etc. / The vertical measurement, top to bottom, for example for clearance under a bridge.

(journalism) The heading or title of a magazine or newspaper article. / (printing, dated) The line at the top of a page containing the folio or number of the page.