centesimus

Centesimus is a Latin term meaning "hundredth." It functions as an ordinal numeral and as the noun for the hundredth part. In Latin, the masculine form is centesimus, the feminine centesima, and the neuter centesimum. It is built from centum "hundred" plus the ordinal suffix -esimus, and appears in classical and medieval texts to express fractions, such as centesima pars, the hundredth part.

In usage, centesimus can denote one hundredth in mathematical or legal contexts. The term occurs in inscriptions and scholastic writings to specify fractions or ordinals. A notable modern usage is the papal encyclical Centesimus Annus (1991) by Pope John Paul II, whose title means "The Hundredth Year" and commemorates the centennial of Rerum Novarum (1891).

Relationship to related terms emerges from the shared root cent- meaning hundred. This root appears in English derivatives such as cent and centi-, and in the word percent, which ultimately derives from per centum, "by the hundred." The form centesimus and its compounds illustrate how Latin numerals influenced later mathematical and legal vocabulary.