Do you have a euro?
I saw the above sentence and do not understand why you say "a" instead of "an"?
You say Do you have "an" umbrella?, but Do you have "a" pound?
Do you have a euro?
I saw the above sentence and do not understand why you say "a" instead of "an"?
You say Do you have "an" umbrella?, but Do you have "a" pound?
Because "U" is here a semi- vowel/ semi - consonant. The same way "w" is a semi- vowel. When they stand at the beginning of a word, they operate as virtual consonants, so the "an" - which is only used for words whose first sound is a vowel- doesn't work.
A few words to exemplify this: union, university, yahoo, yellowish, yell, winner, wimp, walk, yen.
You would use "a" and not "an" with these words.