means The act of producing musical sounds with your voice, shaping pitch and melody as you go.

from From Old English 'singan,' to sing or chant, with deep Germanic roots — a cousin of German 'singen' and Dutch 'zingen.' The same family gave us the noun 'song' (Old English 'sang'), the thing that comes out when you sing. Scholars trace it to a Proto-Germanic root that may have carried the broader sense of reciting or telling aloud, back when song and story were the same act.