I’m going to be honest here. I have only ever seen prerequisite written perquisite when the writer clearly meant the former. And I didn’t actually know what a perquisite was until I looked it up when I sat down to write this post. But just in case you ever need to know … here you go!
A prerequisite, which is the word I really feel most people will be looking for and using out of this pair, is a thing which is required or necessary as a prior condition to something else. So a prerequisite for working as a French teacher is the ability to speak French. A prerequisite for being a proofreader is being able to spell. Oh, and it’s one word: no hyphen.
A perquisite, it turns out, is a special right or privilege that you enjoy as a result of your position. I would say a perquisite of being a freelancer is the ability to wear pyjamas all day, but I don’t think that’s what it’s really about: it’ll be something to do with those special rights to walk your sheep over London Bridge or some such. If anyone reading this actually HAS a perquisite, I’d love to know!
Stop press: My clever friend Jen pointed out – rightly – that the word perk comes from perquisite. A perk is a benefit to which one is entitled to as an employee (or shareholder) of a company and, by extension, a benefit or advantage that comes from a particular situation. I still miss my borrowing perks from when I worked at the library. Interestingly, the dictionary says that this is an abbreviation dating from the 19th century. Thanks, Jen!