Bear with me here.
“For nearly three centuries, French mathematician Blaise Pascal was credited with building the first mechanical calculator. Then, in 1935, historian Franz Hammer discovered papers proving that German mathematician Wilhelm Schickard had beaten Pascal to it by 18 years. But in 1661 Pascal initiated a world first that has not been discredited: he conceived the world’s first bus service, proposing that a number of coaches should “circulate along predetermined routes in Paris at regular intervals regardless of the number of people,” and pick up passengers for a small fixed fare. The word bus is short for omnibus , which means “for everyone.” It was first used in this sense circa 1823, and referred to the fact that anyone could join the coach along its route, unlike stagecoaches, which had to be pre-booked.” - merriam-webster . com
History and Etymology for omnibus
Noun and Adjective
French, from Latin, for all, dative plural of omnis - merriam-webster . com
“Octopi is the oldest plural of octopus , coming from the belief that Latin origins should have Latin endings.” - merriam-webster . com
So if bus is the shortening of omnibus, which has Latin origins, should it’s plural not have the Latin ending? Following the pattern of other such words where the “us” is dropped and replaced with an “i”, if the plural of octopus is octopi, and the plural of fungus is fungi, the plural of bus must be bi.
Example:
“There was a total of seven school bi in the parking lot.”