Phil Druker/Department of English/ University of Idaho

 
The Apostrophe '

Use the apostrophe (') to show possession and contractions (omission).
 
  1. To show possession:

    [singular]
    1. The individual's rights are protected . . . (his/her)
      The rights of the individual . . .
    2. I stepped on the cat's tail.
    3. She earned a bachelor's degree in chemistry.
    4. New York city's problems. . . .
    5. Michelson and Morley's experiment on the velocity of light. . . .
    6. The difference between Tom's and Mary's test scores is small.
    7. The actress's hair (also actress'). . . . (her hair)
      The Jones's house (also Jones') . . . .
      The boss's desk. . . .

    [plural]

    1. The individuals' rights . . . . (their)
      The rights of the individuals
    2. I stepped on the cats' tails. (their tails)
    3. Big cities' problems. . . .
      d. The actresses' hair. . . . (their hair)
      The bosses' desks. . . . (their desks)

    Note: Possessive pronouns never appear with an apostrophe:
    my/mine, your/yours, his, hers, its, ours, whose, theirs
     

  2. To show contractions (omission):
    1. I can't go. = I cannot go.
    2. It's a nice day. = It is a nice day.

      Remember: Who's = who is

    Note: Do not use an apostrophe for the plural of abbreviations or dates.

    1. the 1960s
    2. two CPUs
    3. three RNs
    4. several Ph.D.s1
       

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