Generally

• Latency
• Response time

Law

• To delay payment of a debt, a crime in the United Kingdom

Telecommunications and broadcasting

• Broadcast delay, a practice of time-shifting transmissions
• Delay encoding, a radio transmission technique
• Network delay, the delay of an IP packet within an IP network
• Lag

Physics and electronics

• Propagation delay, a measurement of the time for a signal to reach its destination
• Delay line, one of any technologies for shifting a signal in time

Audio

• Delay , a technology for producing delayed playback of an audio signal

Computer science

• Delay , a programming language construct for delaying evaluation of an expression

Music

• Delay a punk-pop band from Columbus, Ohio signed to Plan-It-X Records
• Delay is a band from Estonia.

Transportation

• Delay, doing something later than was scheduled (e.g. in a timetable), often with overtones of thereby causing inconvenience (see public transport timetables, airline timetables, traffic order, schedule, sailing list etc.)