Punctuation. Apostrophes

    The content of these guidelines is taken from the third edition of the Vives University Network’s Interuniversity Style Guide for Writing Institutional Texts, an interuniversity project in which the UPC participates with the support of the Secretariat for Universities and Research of the Government of Catalonia.


    Apostrophes for possessive forms of nouns

    • The possessive form of a singular noun is marked by an apostrophe followed by s.

      the manager's report the lecturer's hypothesis
      • This rule applies in most cases even with a name ending in -s.

        the PAS's response Erasmus's success
        • If a plural noun already ends in -s, the apostrophe is used alone.

          the students' work (several students)         the teachers' room (all the teachers)
        • Note that the apostrophe is also used in expressions of time periods.

          eight weeks' time yesterday's meeting
        • Degree titles should be written with an apostrophe followed by s.

          bachelor's degree master's degree
        • But note the exception: doctoral degree (not doctor's degree).
        • Do not use apostrophes to indicate a decade, a plural acronym or the plurals of figures.

          the 1990's
          the 1990s

        Apostrophes for contractions

        • Use apostrophes for contractions (you're for you are, don't for do not, it's for it is or it has) but note that contractions are far less common in formal texts than they are in informal writing.