Apocopation is a linguistic term given to the practice of shortening specific words when they precede certain other words. This occurs in Spanish with nine fairly common words.

Most commonly, certain words drop the final letter ‘o’ when they come before a masculine, singular noun.

uno (“a/one”): un libro (a book)

alguno (“some”): algún dinero (some money)

ninguno (“no/not one”): ningún gato (no cat)

bueno (“good”): el buen doctor  (the good doctor)

malo (“bad”): un mal hombre (a bad man)

primero (“first”): primer encuentro (first encounter)

tercero (“third”): tercer piso (third floor)

Variations on the pattern:

Grande: The singular grande is shortened to gran before a noun-whether it be male or female:  In that position, it usually means “great”: un gran hombre (a great man). However, grande is not apocopated when following más: la más grande casa (the greatest house)

Ciento: The word for one/a hundred is shortened before a noun or when used as part of a number: cien libros (100 books) or cien dólares (100 dollars). However, ciento it is not shortened within a number: ciento veinte mil dólares ($120,000).

Cualquiera: When used as an adjective, cualquiera (“any” in the sense of “whatever”) drops the final ‘a’ before a noun-whether it be male or female: cualquier día (whatever day).

Santo: The title for a saint is shortened before the names of most males: San Francisco (Saint Francis). However, it is not shortened if the name it precedes begins with Do- or To- (Santo Domingo)