What is apocapation?

There is a certain group of adjectives in Spanish which need to be shortened- only in front of MASCULINE SINGULAR NOUNS. This is called apocapation. The adjectives are: -Uno (un hermano) -Primero (el primer piso) -Tercero (el tercer piso) -Bueno (un buen hombre) -Malo (el mal tiempo) -Alguno (algun dia) accents on u and I -Ninguno (no tengo ningun dinero) accent on the u -Grande (Grande is the only adjective which apocapates with the feminine singular word too) e.g. gran hermano/ la gran alfombra