clepsydra

noun clepsydra

• 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.
• 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.
• 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.
• chronometer — A chronometer is an extremely accurate clock that is used especially by sailors at sea.
• 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.