gather momentum/strength

:  to bring together :  collect

:  pick, harvest

:  to pick up or amass as if by harvesting

:  something brought together: such as

:  a puckering in cloth made by gathering (see ¹gather 7a)

:  a mass of molten glass collected for use in glassblowing

:  a property (see property 1a) of a moving body that the body has by virtue of its mass (see ²mass 1c) and motion and that is equal to the product of the body's mass and velocity

:  a property of a moving body that determines the length of time required to bring it to rest when under the action of a constant force or moment

:  strength or force gained by motion or by a series of events

:  the quality or state of being strong :  capacity for exertion or endurance

:  power to resist force :  solidity, toughness

:  power of resisting attack :  impregnability