The correct choice of the “articles” a and an depends on the initial sound of a word, not on the initial letter, of the word that they precede.
The letter a should be used before all words beginning with a consonant sound except silent h (an honor) and before words beginning with vowels that represent combined consonant and vowel sounds (university, unit).
Examples: a boy, a European, a j, a picture, a store, a table, a bottle, a window, a phone, a hyphen, and a one-horse town.
There are also words that begin with vowels that have a consonant sound. Say “unique” out loud and you will hear that it contains in its first syllable a consonant y sound as well as the vowel oo sound. You are saying (phonetically) yoo-NEEK. Similarly, “union”, “use”, and “eulogy” begin with a consonant y sound and call for the article a. If you use your ears, you will never be guilty of “an historic” or “an unique.”
Let’s repeat and expand this concept: a is used in front of words that begin with a long u (when pronounced as yoo), eu, and ew, and before the word one. Examples: a united country, a usurper, a eulogy, a ewe, a U-boat, a European, a one-horse town, and many a one.
The word an should be used before all vowel sounds (a, e, i, o, u). Examples: an entry, an f, an hour, an orange, an ape, an odor, an idea, an eagle, an honor, an umbrella, and an unbeliever.
One of the most common mistakes, both written and oral, is the use of an before “historical” or “historic”. When the word following the article begins with a consonant sound, the article used is a; when it begins with a vowel sound, the article used is an.
So remember, a word may in fact begin with a consonant, yet have an initial vowel sound. The word “honest” is a case in point. Say it out loud and you will see what is meant.
The initial consonant h is silent, so the word has an initial vowel sound; hence, an honest man, an hour ago, an heir to the throne, an honest and an honorable peace; on the other hand, when a word begins with an aspirated h (a speech sound followed by a puff of breath or the speech sound represented by English h), correct usage is a hotel, a house, a hill, a hymn, a honeycomb, and a history or a historical.
2. Used to ask someone to repeat something: Slim was only three feet tall!
"Eh? How's that again?"3. Urging someone to agree: Let's have another drink, eh?
This use of eh occurs especially in British and Canadian English.
A Canadian was chatting with a friend who asked, “What I described makes a lot of sense, eh?"
Many states and federal governments tax energy extraction in this manner.
Ad valorem also refers to taxes as "In proportion to invoiced value of goods." A term used when imposing customs and stamp duty, the duty increasing according to the value of the transaction of goods involved.
A reference to an aqueduct that was used to supply water to the city of Rome. During the Republic, aqueducts, and the water supplied, were cared for by water companies hired under contract by the censors.
This abbreviation (aq.) is used with several adjectives that have applications for medical or pharmaceutical instructions:
- aq. astr. (aqua astricta), frozen water
- aq. bull. (aqua bulliens), boiling water
- aq. com. (aqua communis), common water
- aq. dest. (aqua destillata), distilled water
- aq. ferv. (aqua fervens), hot water
- aq. frig. (aqua frigida), cold water
- aq. mar. (aqua marina), sea water
- aq. pluv. (aqua pluvialis), rain water
- aq. pur. (aqua pura), pure water
- aq. tep. (aqua tepida), tepid water
2. The alpha of the alphabet.
3. Something present in each day, yet absent from every morning, noon, and night.
2. A unit of electrical current or rate of flow of electrons.
One volt across one ohm of resistance causes a current flow of one ampere.