lock·up / ˈläkˌəp/ • n. 1. a jail, esp. a temporary one.2. the locking up of premises for the night. ∎  the time of doing this: hurrying back to their dorms before lockup.3. the action of becoming fixed or immovable: anti-lock braking helps prevent wheel lockup.4. an investment in assets that cannot readily be realized or sold in the short term.

LOCKUP

A place of detention in a police station, court or other facility used for persons awaiting trial. In corporate law, a slang term that refers to the setting aside ofsecuritiesfor purchase by friendly interests in order to defeat or make more difficult a takeover attempt. A lockup option is a takeover defensive measure permitting a friendly suitor to purchase divisions of a corporation for a set price when any person or group acquires a certain percentage of the corporation's shares. To be legal, such agreement must advance or stimulate the bidding process, to best serve the interests of the shareholders through encouraged competition.