What is the meaning of Tilting?

present participle and gerund of tilt

The motion of something that tilts; a tilt.

The process by which blister steel is rendered ductile by being forged with a tilt hammer.

A charging with a lance, as in jousting.

Having the property that it is the quotient of a projective module by a projective submodule, having an ext functor with itself of 0, and there being a right module as the kernel of a surjective morphism between finite direct sums of its direct summands.

Source: wiktionary.org