To differentiate similar things.

(idiomatic) To reverse a situation, so that the advantage has shifted to the party which was previously disadvantaged.

(physics) A theorem in mechanics showing the relationship between the kinetic energy of a system to the virial of Clausius.

(idiomatic) Free from work or direct supervision. In reference to slave labor, where workers are chained, or to the figurative chain of workers of an assembly line.

noisy, opinionated people are often ignorant.

A junction in which one road becomes two divergent roads / (by analogy) A point where a choice, one of two possibilities has to be taken.

(conjunctive) Opposite of what had earlier been expected or assumed.

(mathematics) the probability that a certain outcome will occur, as determined through reasoning or calculation.

(UK, informal) All over the place.

Used other than figuratively or idiomatically: see add, fuel, fire. / (idiomatic) To worsen a conflict between people; to inflame an already tense situation.