calendar — A calendar is a chart or device which displays the date and the day of the week, and often the whole of a particular year divided up into months, weeks, and days.
chronograph — an accurate instrument for recording small intervals of time
chronometer — A chronometer is an extremely accurate clock that is used especially by sailors at sea.
chronoscope — an instrument that registers small intervals of time on a dial, cathode-ray tube, etc
clepsydra — an ancient device for measuring time by the flow of water or mercury through a small aperture
clock — A clock is an instrument, for example in a room or on the outside of a building, that shows what time of day it is.
dial — A dial is the part of a machine or instrument such as a clock or watch which shows you the time or a measurement that has been recorded.
gnomon — the raised part of a sundial that casts the shadow; a style.
horologe — any instrument for indicating the time, especially a sundial or an early form of clock.
hourglass — an instrument for measuring time, consisting of two bulbs of glass joined by a narrow passage through which a quantity of sand or mercury runs in just an hour.
metronome — a mechanical or electrical instrument that makes repeated clicking sounds at an adjustable pace, used for marking rhythm, especially in practicing music.
pendulum — a body so suspended from a fixed point as to move to and fro by the action of gravity and acquired momentum.
stopwatch — a watch with a hand or hands that can be stopped or started at any instant, used for precise timing, as in races.
sundial — an instrument that indicates the time of day by means of the position, on a graduated plate or surface, of the shadow of the gnomon as it is cast by the sun.
watch — to be alertly on the lookout, look attentively, or observe, as to see what comes, is done, or happens: to watch while an experiment is performed.
alarm clock — An alarm clock is a clock that you can set to make a noise so that it wakes you up at a particular time.
