The adjectives a, an, and the are called Articles.
A and an are Indefinite Articles; the is a Definite Article. Their distinctive uses are shown in the following sentences.
Hand me a pencil (any pencil).
Hand me the pencil (a particular pencil).
The indefinite articles indicate a member of a class without designating which particular one; the definite article indicates a specific member or members of a class.
Uses of “A” and “An.” (1) The article a precedes a word beginning with a consonant sound; an precedes a word beginning with a vowel sound: a tree, an olive tree.
Note. Besides the common vowels of a, e, i, o, and u, in English a y can have the characteristics of either a vowel or a consonant. That is, an initial y is almost always a consonant (yell, yard); in the middle of a word, it is often a vowel (analysis).
(2) The letter u can have either a vowel or a consonant sound. Before a word beginning with a u having a vowel sound, an is used: as, an understanding, an uncle; before a word beginning with a u having a consonant sound, a is used: as, a union (pronounced yunion), a uniform, a use.
(3) Before a word beginning with h, an is used if the h is silent; a is used if the h is sounded: as, an honorable profession, a humid day, a house.
Adherence to the above rule is not universal. Some writers use a before a word beginning with h if the first syllable is accented and an if it is unaccented: as, a his´-tory; an his-tor´-ical event. However, this practice is not recommended.
Also on Facebook and Twitter. All content (c) Thomas Fasano 2014. Any other copyrighted material is included as “fair use”, for the purpose of study, review or critical analysis only, and will be removed at the request of copyright owner(s).