- A state in which two oscillating systems are synchronized at the same frequency. Also, the process by which this synchronicity is achieved. For example, the shifts of one or both systems, followed by their being locked in place.
- noun a drinking session taking place in a pub after official closing time. The practice, which usually involves locking out late arrivals, hence locking in the existing clientele, is illegal but sometimes unofficially condoned by local police. A more fashionable term is afters.
- noun a session of after-hours drinking inside a pub