Use the apostrophe before an "s" to indicate the possessive (i.e. something that is of or belonging to something else – the graduating class of Memorial).
- Memorial’s graduating class
If something is descriptive rather than possessive, it does not take an apostrophe (the guide for students, the college for teachers, the point guard for the Sea-Hawks).
In cases where the noun ends in an "s", use a single apostrophe after the "s".
- The Faculty of Business’ student teams
- Professor Bridget Jenkins’ research
Note that the "s" followed by an apostrophe reads awkwardly, so it might be better to rewrite the sentence.
- Student teams in the Faculty of Business
- Research by Professor Bridget Jenkins
In cases where the possessive is plural, use a single apostrophe after the "s" or rewrite the sentence.
- The students’ grades will be posted.
- The senators’ votes were counted at the end of the meeting.
- Grades will be posted.
- At the end of the senate meeting, the results of the vote were counted.
Use an apostrophe with plurals of lower case letters.
- Mind your p’s and q’s. Dot the i’s and cross the t’s.
Capital letters and numbers have no apostrophe before plural-s.
- She got straight As. We teach the three Rs.
- The 1960s was a decade of rapid growth for York University.
Do not use an apostrophe with the possessive pronoun "its".
- The program is in its third year.
Use an apostrophe with the contraction meaning "it is".
- It’s a difficult course.
(See the Possessives section.)