Woman is singular; women is plural
Here?s one that people get wrong all the time. Women is the plural form of woman ? so one woman, many women. They?re pronounced differently: woman sounds like woo-man, whereas women sounds more like whim-en.
The exception to the rule
The exception to the pronunciation rule is if you?re from New Zealand. For some reason, Kiwis like to pronounce women the same way as woman, which is just confusing for everyone. (But you do you, Kiwis!)
How to remember the difference
How can you remember to spell them correctly?
It?s very easy. Take a look at the last three letters of both words. That?s right ? they?re based off man and men. Since pretty much nobody has a problem remembering whether to use man or men, just figure out whether man or men would work in your context, and use woman or women accordingly.