dial [ME] The earliest senses of dial were ‘a mariner’s compass’, ‘sundial’, and ‘the face of a clock or watch’—all round objects marked out with gradations. The old slang meaning ‘a person’s face’ would have been suggested by the fact that faces are roundish. The word’s immediate source was medieval Latin diale ‘clock dial’, which came from Latin dies ‘day’, also the source of diary [L16th]. See also clock.