shake

Shake is a verb meaning to move something rapidly back and forth or up and down, or to cause such motion. It is also a noun referring to the act of shaking or to a tremor in a person, object, or structure. The word comes from the Old English scacan; its principal verb forms are shake, shook, and shaken.

In physics and engineering, shaking describes enforced or spontaneous oscillation. In daily life, people shake their bodies or heads, or shake containers to mix contents. In seismology, ground shaking is the motion of the ground during an earthquake, and shaking tables and shakers are used to test materials and structures under dynamic loads.

In food and beverages, a shake is a blended drink, typically made with milk and ice cream or a milk substitute; common flavors include chocolate, vanilla, and strawberry. A protein shake refers to a drink containing protein powder. The term "shake" is often used informally to refer to such beverages.

Common phrases include 'handshake' (a greeting formed by briefly shaking hands) and phrasal verbs such as 'shake off' (to get rid of something) and 'shake up' (to reorganize or energize). The noun 'shakedown' describes a coercive demand or inspection, and 'shake-down' is a variant spelling.