The rules for apostrophes vary with the type of word. Learn where to put apostrophes so that your writing is clear and correct. In short, apostrophes are frequently used to indicate possession and in contractions, but never to pluralize.
Never use an apostrophe to indicate a plural. The wrong use of an apostrophe to form the plural is called the greengrocer’s apostrophe, since grocers are often the worst (or at least the most visible) offenders. If you have more than one apple, then write apples, not apple’s. If you cannot replace the word with “his,” “her,” “their”, or “its” and if it isn’t a contraction, then an apostrophe should not be used.
- People often forget the rules when a word ends in a vowel, such as the word “mango.” Many people write “mango’s” instead of “mangos” or “mangoes“.
- An exception to this use is in the case of making a single letter plural. Therefore, Why are there so many i’s in the word “indivisibility”? is correct. This is simply for clarity reasons, so the reader does not mistake it for the word “is.” However, in modern usage, the preference is to avoid inserting an apostrophe and instead surround the single letter in quotation marks before pluralizing it: Why are there so many “I”s in the word “indivisibility”?
- Apostrophes are never used in plurals, no matter what the personal preference is. “Do’s and don’t’s” is wrong; the correct form is “dos and don’ts”.
- Making an exception for numbers and abbreviations is not current practice. MLA guidelines suggest that no apostrophe is needed following numbers (as when naming a decade). “I bought many CD’s in the 1990’s.” is wrong; the correct form is “I bought many CDs in the 1990s.”