liftoff

or lift-off

[ lift-awf, -of ]
/ ˈlɪftˌɔf, -ˌɒf /

noun

Aeronautics, Rocketry.
  1. the action of an aircraft in becoming airborne or of a rocket in rising from its launching site under its own power.
  2. the instant when such action occurs.
Informal. the launching or commencement of a project, plan, etc.: The liftoff of the sales campaign will be next month.

adjective

that removes by lifting off; capable of being lifted off: a liftoff correction tape for typewriters; magnetized, liftoff nameplates.

Origin of liftoff

First recorded in 1955–60; noun, adj. use of verb phrase lift off

British Dictionary definitions for lift off

liftoff
/ (ˈlɪftˌɒf) /

noun

the initial movement or ascent of a rocket from its launch pad
the instant at which this occurs

verb lift off

(intr, adverb) (of a rocket) to leave its launch pad

Idioms and Phrases with lift off

lift off

Begin flight, as in The spacecraft was due to lift off at ten o'clock. The off in this idiom means “off the ground.” [Late 1800s]