Dear Dr. Grammar,
I am puzzled by the apostrophe. When do I use “it’s”, and when do I use “its”? And, more widely, what are the rules on using apostrophes and extra s-es with plural possessives? It’s all so confusing!
– Mr. A.P. O’Strophe
Ah, the apostrophe! That sassy upwardly mobile comma, not quite as confusing as its lower sister but more than enough trouble in its own right. Starting this column as I mean to go on, I’m going to answer your question by giving you a straight answer, then supplying a bit of history that might help that answer stick, then giving a more in-depth explanation of the logic behind the usage.
Firstly: “It’s” is a contraction for “it is.” It is only that – in fact, it’s only that. If you want to use a shortened version of “it is,” you want to use “it’s.” If you want to do anything else involving it and s – which means, if you want to use the possessive of it – you use its.
Grammar is a cruel mistress
When it comes to other possessives, things are more complicated. Around about 1550, possession was indicated by the use of his – for example: “Harry his book.” As English became more standardised, this contracted – so you’d say, “Harry’s book.” A useful way to remember that possessives take an apostrophe + s, is to remember this bit of history (if you’re wondering why women don’t get apostrophe + r, as in “Sally her book,” “Sally’r book,” the answer is that back then women didn’t come into it. Most women couldn’t even read, and if they were married nothing belonged to them. Go feminism!). Given that explanation, it’s/its is clearly a bit of an outlier. It’s counterintuitive, I know. What can I tell you? Grammar is a cruel mistress.
But what about other names and nouns, I hear you cry? What about Paris? What about Keats? First, the broad rule: you form the possessive of most singular nouns by adding an apostrophe and an s. You form the possessive of most plural nouns by adding only an apostrophe. This means human becomes human’s (as in “It is that human’s femur”), and humans becomes humans’ (as in, “They are those humans’ femurs”).
In the case of singular nouns, even those ending in an s get an apostrophe + s to form the possessive. It really is Keats’s, Paris’s, Venus’s, and so on (notice that in these cases the final s sound of the name is usually a soft s, “ssss,” while the possessive s is a hard s, “zzz.” This is why you don’t run into the pronunciation problem that you do with humans’s).
There are two-and-a-half exceptions to this rule. The first exception is for any name of two or more syllables that ends in an eez sound, like Socrates or Ganges. These only get an apostrophe – again, an added zzz sound would make them awkward to pronounce. So they are just Socrates’, Ganges’.
The second exception is words that are plural in form but singular in meaning, for example species or states. These also only take an apostrophe: species’, states’ (as in States’ Rights). It looks weird, but it’s correct.
The half exception is the hotly contested issue of Names with a Silent S. What is one to do about the possessive of Descartes? Of Camus? Here, the answer is very much down to the conscience of the individual writer. You may use the apostrophe on its own – Descartes’ – or you may use the apostrophe + s – Descartes’s. Each has its followers, so either is permissible. Dr. Grammar prefers Descartes’s, but you don’t have to.
You will not mkae any greengrocer friends by pointing out that their signs are incorrect
You don’t use an apostrophe to form a plural. Pretty simple rule, eh? Plurals of abbreviations (WMDs), plurals of dates (1990s), plurals of numbers (fours): none of them get an apostrophe.
As it happens, the error of putting an apostrophe in a plural has its own name: it’s called The Grocer’s Apostrophe. This is because you will frequently see greengrocers’ signs that say, “Lettuce’s,” or “Apple’s.” Remember: you will not make any greengrocer friends by pointing out to them that their signs are mechanically incorrect; just buy one of their apple’s and let it be.
So that’s the apostrophe done and dusted. If you have any other questions, feel free to ask. Remember, you can trust me: I’m a doctor.
Puzzled by the passive? Confused about commas? Wishing you were less wordy? Ask Dr. Grammar your grammar or mechanics question, and she’ll help. Send your questions to firstname.lastname@example.org