A, An

  • Use a before words that start with a consonant or a “yew” sound:
    • A university
    • A hacker
  • Use an before words that start with a vowel or an unsounded consonant:
    • An hour
    • An electrical engineer
  • If an acronym is generally read as alphabetic letters, choose the article according to the first letter:
    • An API
    • A URL
  • Add a, an, the, and other articles for ease of reading, both in text and lists that consist of complete phrases.