Spanish nouns come in two genders: masculine or feminine. So when a direct article is used (in English, the direct article is “the”... as in “the apple” or “the notebook” instead of just apple and notebook) you must know whether to use the masculine or feminine article (el or la, respectively). In fact, most of the nouns you learn and practice in Spanish 101--and onward--will be learned in conjunction with the direct article. You won't be memorizing pared and carro; you'll be asked to remember la pared and el carro.
As a general rule, words ending in “a” receive the feminine direct article (la) and words that end in “o” receive the masculine direct article (el). Here are a few examples:
la mesa (table)
la camisa (shirt/blouse)
el sombrero (hat)
el consejo (council; also can be used to refer to advice)
There are some exceptions to this general rule; you'll pick them up as you go. Here are a few examples of exceptions:
la mano (hand; note that even though “mano” ends with -o, it still receives the feminine article)
el taxista (a male taxi driver; a female driver would be “la taxista”)
el tema (subject, issue or theme; note that even though the word ends with -a, it still receives the masculine article)