L’ARTICOLO INDETERMINATIVO THE INDEFINITE ARTICLE A/AN

UN UN is used before all masculine nouns. *USUALLY ALL MASCULINE NOUNS END IN “O.”  UN TRENO  UN AEROPLANO  UN LIBRO

UNO UNO is used before all masculine nouns that begin with “Z or S+CONSONANT”  UNO ZAINO  UNO STADIO  UNO STUDENTE

UNA UNA is used before all feminine nouns. Usually all feminine nouns end in an “A.”  UNA FARMACIA  UNA SCUOLA  UNA ZIA  UNA STUDENTESSA

UN’ UN’ is used with all feminine nouns that begin with a “VOWEL.”  UN’UNIVERSITA`  UN’AMICA  UN’ARANCIATA *UNA BECOMES UN’ BECAUSE UNA ENDS IN AN A. IT BECOMES CONTRACTED WITH AN APOSTROFE FOR PRONUNCIATION REASONS.