To make something larger fit in a smaller or tight place with brute force

Because of

The impulse to work persistently until one's desires realize themselves; determination.

Power gained purely from desire or will.

plural of forcefulness

The effect of greenhouse gases on the radiation of heat in the atmosphere.

plural of forcing function

(mathematics) A function in a system of differential equations that is only a function of time, unaffected by the other variables; or, more generally, any non-homogeneous source function in any variable.

A place where plants are forced into maturity sooner than would naturally happen. / (figuratively) Any place that promotes early development.

plural of forcing house