Another case where this rule applies is when acronyms or initialisms start with consonant letters but have vowel sounds:
If the noun is modified by an adjective, the choice between a and an depends on the initial sound of the adjective that immediately follows the article:
- a broken egg
- an unusual problem
- a European country (sounds like 'yer-o-pi-an,' i.e. begins with consonant 'y' sound)
Remember, too, that in English, the indefinite articles are used to indicate membership in a group:
- I am a teacher. (I am a member of a large group known as teachers.)
- Brian is an Irishman. (Brian is a member of the people known as Irish.)
- Seiko is a practicing Buddhist. (Seiko is a member of the group of people known as Buddhists.)
DEFINITE ARTICLE: THE
The definite article is used before singular and plural nouns when the noun is specific or particular. The signals that the noun is definite, that it refers to a particular member of a group. For example:
"The dog that bit me ran away." Here, we're talking about a specific dog, the dog that bit me.
"I was happy to see the policeman who saved my cat!" Here, we're talking about a particular policeman. Even if we don't know the policeman's name, it's still a particular policeman because it is the one who saved the cat.
"I saw the elephant at the zoo." Here, we're talking about a specific noun. Probably there is only one elephant at the zoo.
COUNT AND NONCOUNT NOUNS
The can be used with noncount nouns, or the article can be omitted entirely.
- "I love to sail over the water" (some specific body of water) or "I love to sail over water" (any water).
- "He spilled the milk all over the floor" (some specific milk, perhaps the milk you bought earlier that day) or "He spilled milk all over the floor" (any milk).
"A/an" can be used only with count nouns.
- "I need a bottle of water."
- "I need a new glass of milk."
Most of the time, you can't say, "She wants a water," unless you're implying, say, a bottle of water