among mathematicians, a term for such things or quantities as are given or known, by which to find things or results that are unknown. The data of Euclid form the first in order of the books which have been written by the ancient geometers, to facilitate the method of resolution or analysis.

From the primary use of the word data in mathematics, it has been transplanted into other branches, as philosophy, medicine, and the like, where it expresses any quantity which, for the sake of a present calculation, is taken for granted to be such, without requiring an immediate proof of its certainty; which is also called the given quantity, number, or power. And hence also such things as are known, and from which, either in natural philosophy, the animal mechanism, or the operation of medicine, we come to the knowledge of others unknown, are now by physical writers frequently termed data.