early 15c., "sundial," earlier "dial of a compass" (mid-14c.), apparently from Medieval Latin dialis "daily," from Latin dies "day" (see diurnal).
The word perhaps was abstracted from a phrase such as Medieval Latin rota dialis "daily wheel," and evolved to mean any round plate over which something rotates. Telephone sense is from 1879, which led to dial tone (1921), "the signal to begin dialing," which term soon might be the sole relic of the rotary phone.
1650s, "to work with aid of a dial or compass," from dial (n.). Telephone sense is from 1923. Related: Dialed; dialing.
for the measurement of time, only once mentioned in the Bible, erected by Ahaz (2 Kings 20:11; Isa. 38:8). The Hebrew word (ma'aloth) is rendered "steps" in Ex. 20:26, 1 Kings 10:19, and "degrees" in 2 Kings 20:9, 10, 11. The _ma'aloth_ was probably stairs on which the shadow of a column or obelisk placed on the top fell. The shadow would cover a greater or smaller number of steps, according as the sun was low or high. Probably the sun-dial was a Babylonian invention. Daniel at Babylon (Dan. 3:6) is the first to make mention of the "hour."