Definite and indefinite articles | The parts of speech | Grammar | Khan Academy
So we've covered the basic idea that divides the usage of the from "a" and "an." You know, "the" is the definite article, and "a" or "an" is the indefinite. So when you're being non-specific in language, you would use the indefinite article, as in "May I have an orange?" Because it doesn't matter which orange you're asking for; you don't care. It's any orange.
As opposed to if you wanted "the orange," this usage is much more specific, and it seems to indicate that there is only one orange. You see the orange in particular that you want; you're identifying it, and you're asking for it. That's what this definite usage is. Something that's interesting about the word "the" is that it can be used for both singular and plural nouns.
So it's both singular and plural. You could say, "May I have the orange?" You could also say, "May I have the oranges?" "A" and "an" does not really allow this; it is only singular. So you can't say, "May I have an oranges?" This is not standard. What you would probably say instead was, "May I have some oranges?" This is not standard; it does not work in standard American English.
The other thing about "a" or "an" is that it's "a" or "an." The indefinite article changes depending on the vowel sound that comes after it, so it changes for vowel sounds. Now, what does that mean? Well, it means that if you know that the word that you're going to say next starts with "a," "e," "i," "o," or "u," then you're going to change it to "an."
So it's the difference between saying "a box" and "an apple." And what we don't say in standard American English is "a apple." It's not as easy on the mouth, frankly. It takes a little bit more effort, and any linguist will tell you that the way languages develop is that they reward laziness.
So we say "a box," but we say "an apple." Something a little weird, though: you want to make sure that you're looking for vowel sounds, not just for vowels. Because some vowels, for example, the letter "u," don't always produce the "oo" sound. Sometimes, if they're at the beginning of a word, like in the word "union," if you say "a union," that produces a "y" sound.
And "y" is technically a consonant sound; it's not a vowel. But there are certainly cases, like "an underwater boat," where the letter "u" does produce an "u" sound, and that's a vowel. So if you're going to start the word with a vowel sound, what you want to do is choose "an" instead of "a," but just be careful of the letter "u," for example.
So to recap: "the" is the definite article; you can use it for both singular and plural usage. "May I have the orange?" "May I have the oranges?" "A" or "an" is indefinite, and it's only singular. So you can say "may I have an orange" or "may I have some oranges." Before a vowel sound, "a" changes to "an," so you say "a box" but "an apple," not "a apple." You say "a union" but "an underwater boat." You can learn anything. David out.