cuatrocientos

Cuatrocientos is the Spanish cardinal number that denotes the value 400. It is used to quantify nouns and as part of counting. When the noun is masculine, the form cuatrocientos is used; for feminine nouns the corresponding form is cuatrocientas (for example, cuatrocientos libros, cuatrocientas canciones).

In Spanish, hundreds are expressed with distinct forms for masculine and feminine. The sequence includes doscientos, trescientos, and cuatrocientos, with feminine plurals doscientas, trescientas, and cuatrocientas. The word cien is used for exactly 100; ciento appears in 101–199 (ciento uno, ciento noventa y ocho), whereas 200–900 use the doscientos, trescientos, etc., patterns.

Etymology and related forms: cuatrocientos is formed from cuatro (four) plus cientos (hundreds), with hundreds derived from Latin centum. The modern form reflects the masculine plural of the numeral. In Roman numerals, 400 is CD.

Usage and contexts: 400 appears in mathematics as a perfect square (20 squared). It is also common in measurements and dates, such as cuatrocientos kilómetros or cuatrocientos años. In historical or arithmetic contexts, it may be used similarly to other round numbers.

See also: cien and ciento, doscientos, trescientos, quinientos, and the Roman numeral system for numerals.