Welcome to the Grammar Minute, where we’re saving the English language sixty seconds at a time! I’m Lauren Smyth, and I’m here to introduce a great new word: if. Spelled i-f-f.

This term is borrowed from the realm of mathematics and logic. “If” with one f represents a conditional statement: If I pet a cat, I will sneeze. This doesn’t exclude the possibility that other things could make me sneeze—for example, maybe dogs also make me sneeze. Here’s what’s so special about “if” with two fs: It does exclude other possibilities, meaning “if and only if.” I will sneeze i-f-f I pet a cat means that under no other circumstances will I ever sneeze.

The unfortunate thing about this term is that it’s really only useful in print writing and a lot of people will just assume you’ve made a typo. So, if you’re writing to a non-mathematically-trained audience, you probably want to use the wordy but easily understood “if and only if.” Otherwise, however, the double-f- iff is a great way to get the point across briefly and clearly.

That’s your Grammar Minute! Visit thegrammarminute.com for more tips and tricks.