(law) An agreement in which an offeror's offer can be accepted only by the performance of an act by the offeree; a "promise for a performance".

(music, acoustics) Identical pitch between two notes or sounds; the simultaneous playing of notes of identical pitch (or separated by one or more octaves).

(anatomy) The structure consisting of hair, hair follicle, arrector pili muscle and sebaceous gland.

(geometry) A circle of radius 1. / (trigonometry, the unit circle) The circle of radius 1 with centre at the origin, used in defining trigonometric functions.

A worldwide postal organization, part of the United Nations.

In a uniform manner, consistently.

continuing with no interruption

The flag of the United Kingdom, consisting of the flags of England (St. George's Cross), Scotland (St. Andrew's Cross), and Ireland (St. Patrick's Cross) now only used in Northern Ireland combined.

Not intelligent.

In an unintentional manner; not intentionally.