In Spanish nouns have gender (masculine and feminine) and number (singular and plural). The gender depends on the article to be placed before the noun. El, lo, los are defined articles for males. La, las are defined articles for the female gender. Un, unos are indefinite articles for male, una, unas are indefinite articles for the female gender. For example: La mesa, una mesa (female, sing), Las mesas, unas mesas (female, plural).