“Natatorium” or “My brother is a genius”

Eric and I walked by a building on our way to the Big House and it said something about a "natatorium." Neither of us knew what it was…but the building was the intramural building, so we could speculate it had something to do with sports.

"Maybe it’s a swimming pool," Eric suggested. I tried to break down the word and figure out how it could mean swimming pool, but I couldn’t come up with anything.

As it turns out, Eric was correct. Here’s the definition:

[Late Latin nattrium, place for swimming, from neuter of Latin
nattrius, of swimming, from nattus, act of swimming, from past participle of
natre frequentative of nre, to swim. See natatorial.]