Meaning of AN in English
BAD : I had never visited an hospital before.
GOOD : I had never visited a hospital before.
Before a word beginning with h , use a if the h is pronounced: 'a house', 'a half', 'a horrible day'. Use an if the h is silent: 'an hour', 'an honour'.
If the h is pronounced but the syllable is unstressed, it is possible to use a or an ('a/an hotel'). However, the use of an here is considered old-fashioned and most people use a .
Longman Common Errors English vocabulary. Английский словарь распространенных ошибок Longman. 2012