Wiktionary
n. (context US English) public transport#English.
WordNet
n. a public transportation system for moving passengers
Usage examples of "public transit".
Oh, they may keep a half an eye on public transit, but they won't expect you to have help.
I have a rare high-status permit for a private automobile so that I do not have to ride with anyone else or take the noisy, crowded public transit.
Well, now we know why heroes never rake public transit, he thought as he joined the surging crowd at the back door.
Heris rode a silent electric car hardly big enough for her and the driver from the public transit stop to the entrance, and wondered aloud at the spaciousness.
He was amused to discover that the public transit system was referred to as the TTC (for Toronto Transit Commission).
I don't have much time, and there's even less if I have to take goddam public transit on this job.