The rule of placing an before a vowel is actually to place an before a vowel sound. Therefore, because uniform is pronounced with a “y” sound (/ˈjuːnɪfɔːm/), which is not a vowel sound, it takes an a before it.

Name. Hour is a development of the Anglo-Norman houre and Middle English ure, first attested in the 13th century. It displaced tide tīd, “time” and stound stund, span of time. The Anglo-Norman term was a borrowing of Old French ure, a variant of ore, which derived from Latin hōra and Greek hṓrā (ὥρα).

“Unicorn” describes a person who joins a couple as their third partner, for sex or even for something more committed.

A uniform is correct. Though, uniform starts with U, you should not say ‘an unfirom’. The reson is, pronunciation of uniform is youniform. So, according to pronunciation, the first letter is Y.

All English nouns beginning with the sound of a vowel use the article “an” and all English nouns beginning with the sound of a consonant use the article “a”. “Uniform” begins with a U which is a vowel, but it sounds like a “y” which is a consonant, so it uses the article “a”.

The first phonetic symbol for umbrella is ʌ, a vowel sound, so we say an umbrella. For university, the initial sound is j, a consonant sound, so we say a university. In the next pair, the beginning sound in home is the consonant h so we say a home.

The U in umbrella is pronounced as a vowel sound ( Λ using the phonetic alphabet) and so we use ‘an’. We therefore say ‘an umbrella’. This rule also applies to the use of consonants. The word hour has a soft ‘h’ which is weakly pronounced and therefore we say ‘an hour’.

There is one simple way of remembering this. When the word begins with a vowel sound (a,e,i,o,u) then you should use ‘an’ as it sounds better and feels easier to say. When the word begins with a consonant you should use ‘a’.

The rule is: Use an before a word beginning with a vowel sound (not letter). It doesn’t matter how the word is spelled. Use a before a word with a consonant sound as well as y and w sounds.

It’s “a 100” because when pronounced “a hundred” or “a one hundred,” the word preceded by the article “a” begins with a consonant sound, either “H” or “W,” respectively.

The real rule is this: You use the article “a” before words that start with a consonant sound and “an” before words that start with a vowel sound. The “u” in “unique” makes the “Y” sound—a consonant sound—therefore you use “a” as your article, while the “h” in “hour” sounds like it starts with “ow”—a vowel sound.

English has two articles: the and a/an. The is used to refer to specific or particular nouns; a/an is used to modify non-specific or non-particular nouns. We call the the definite article and a/an the indefinite article. “A/an” is used to refer to a non-specific or non-particular member of the group.