"Maneuver speed" in context is what Boeing calls the minimum safe speed (based on 1.3G, 30 deg bank, + overshoot [or whatever the exact technical criteria are]) for the given flap configuration. It is based on Vref, as 172_driver indicated, so varies with weight. It is NOT the same as Va, which is a common reference for light airplanes (and,
AFAIK, only applies to flaps up).
In general, for the given flap configuration, flap maneuvering speed will give you sufficient stall margin for all normal turning and maneuvering. If you have to fly slower, increase the flap setting.
The 747 schedule is Vref30 +
60 for Flaps 1
40 for flaps 5
20 for flaps 10
10 for flaps 20
5 for flaps 25
0 for flaps 30
Vref30 + 100 is normal safe climb speed with flaps up, and Vref30 + 80 is flaps up maneuvering speed at landing weights (or below 311T).