oldhurchlavonic

As a noun friday is

the sixth day of the week in many religious traditions, and the fifth day of the week in systems using the norm; the biblical sixth day of a week, the day before the sabbath, or "day of preparation" in preparation for the sabbath; the islamic sabbath; it follows thursday and precedes saturday.

As an adverb friday is

on friday.

As a verb equaling is

.

As a noun quantity is

a fundamental, generic term used when referring to the measurement (count, amount) of a scalar, vector, number of items or to some other way of denominating the value of a collection or group of items.