Hyperbole is figure of speech, classified as a thought figure, consisting of exaggerate an idea with expressive purpose. It's an intentional exaggeration of the expression.
For example:
I am thirsty. (instead of being very thirsty)
cried rivers of tears. (instead of crying a lot)
I've told you this a million times. (instead of already told you this several times)
Grammar is a set of rules that establish a particular use of language, called a cultured norm or standard language. These norms are not always obeyed by the speaker, who often deviates from it, in order to reinforce the message, building a new and original message.
Hyperbole is one of those forms, with the purpose of exaggerating or exaggerating the truth of the facts.
Hyperbole in Geometry
In Geometry, hyperbola is the locus of points on a plane whose difference in distances to two fixed points on that same plane is constant. It is the intersection of a straight circular cone with a plane that makes the axis of the cone an angle smaller than that of the vertex.
See too Examples of Metaphors and examples of other figures of speech.