What is the meaning of Lock-in?

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.

An illegal but widely-tolerated invitation-only gathering in a pub, after the end of licensing hours, to allow regular customers the opportunity to enjoy further drinking time.

A situation in which a business has adopted a certain standard or product from a specific manufacturer and integrated it into their process, thus making it very costly to change to a different standard or supplier.

The situation where an investor cannot trade without incurring an undesirable penalty such as taxation.

Source: wiktionary.org