lockin

noun

1. 1.A sleepover party, usually held in a public place such as a church or school, in which the participants are not allowed to leave until the next morning.
2. 2.An illegal but widely-tolerated invitation-only gathering in a British pub, after the end of licensing hours, to allow regular customers the opportunity to enjoy further drinking time.
3. 3.A situation in which members of an industry have agreed to adopt a certain standard and have retooled their production to meet this standard, thus making it very costly to change to a different standard.