Hint
Outside of a room where physics is being discussed, this word is most likely to show up in a crossword puzzle. Such as...
Here's the solution to the crossword:
Solution
The reciprocal of 1 ohm? We'll call it a mho! (Some of you might have noticed that the symbol is an upside-down omega; ohm = Ω and mho = ℧.)
Congratulations to yesterday's winners Atticus, Anna J., Jacob C., Peter M., Maddy, Charlie, Yana, Inca, Jason, Kate, Graham, Dr. Yetman, and Mr. Gregg. Thanks to everybody who made a guess!
Ten years later, Dr. Shapiro revived Puzzle of the Day at Proof School, writing each day's puzzle on a name tag. After 600 puzzles or so, he was just starting to feel normal about students reading his chest all the time when campus closed and the puzzle, like the rest of our lives, moved online. New puzzles are posted daily on school days.
Want to catch up on old PotDs? There's an archive currently containing puzzles from March to December 2020.