What is an kind of article used before a singular word that begins vowel or consonant?

The kind of article used before a singular word depends on whether the word starts with a vowel sound or a consonant sound:

* Before words that start with a vowel sound: Use "an". This includes words that start with a silent "h" (e.g., "an hour").

* Before words that start with a consonant sound: Use "a". This includes words that start with a vowel but have a consonant sound (e.g., "a university").

Here are some examples:

* "an": an apple, an umbrella, an hour, an honor

* "a": a cat, a book, a university, a one-way street

It's important to remember that it's the sound, not the letter, that determines which article to use.