Meaning

noun a line of text serving to indicate what the passage below it is about

noun the direction or path along which something moves or along which it lies

noun a horizontal (or nearly horizontal) passageway in a mine

originEtymology tree Proto-Indo-European *kap- Proto-Indo-European *káput Proto-Germanic *haubudą Old English hēafod Middle English heed English head English -ing English heading From head + -ing.

Etymology from Wiktionary, CC BY-SA 3.0