Articles and Plurals

In spanish, articles are words that begins with "el" or "la" and end in "o" or "a". Plurals are nouns that begins with "los" or "las" and end in "os"or "as".  I also know that when you use masculine words it will begin with "el" and when you use feminine words begins with "la".  Also, there are definite words and indefinite words.  Definite words are would be el, la, los, and las. Indefinite words would be un,una, unos, and unas.