Why do pilots say “rotate” when taking off, also some say it when lowering the nose during landing?

Question

Why do pilots say “rotate” when taking off, also some say it when lowering the nose during landing?

In: 113

Answer 1

V1 – speed at which takeoff cannot be aborted (ie committed to takeoff)
Vr – rotate speed, speed at which pilot lifts nose wheel transition to flight
V2 – take off safety speed (safe engine out climb speed in multi engine aircraft)

V1 and Vr are normally very close together.