yom

Yom is a Hebrew noun meaning "day." In biblical and modern Hebrew it designates the daylight portion of a 24-hour period and functions as a basic temporal unit in speech, writing, and calendar notation. The form appears in countless phrases and in the names of dates and holidays, and it participates in a number of common compound terms.

In Jewish and Israeli usage, yom is central to holiday nomenclature. Yom Kippur means the Day of Atonement; Yom HaShoah is Holocaust Remembrance Day; Yom HaZikaron is Memorial Day for fallen soldiers and victims of terrorism; Yom HaAtzmaut is Israel's Independence Day. The compound Yom Tov denotes a festival day when work is traditionally restricted, and it is often translated as "a good day." In everyday speech, phrases such as yom echad ("one day") and "beyom hazeh" for "on this day" illustrate its role as a time marker.

Linguistically, yom has cognates in other Semitic languages; the Arabic yaum carries the same basic meaning of "day." Outside Hebrew, the string "Yom" can appear in transliterations of names or terms, but its primary sense is as a common noun for time and as a component of holiday names.