English inches.

I'm not sure I ever heard the Italian word oncia as a unit of length. I thought it was a translation of the imperial unit of weight, ounce. However all is possible in the world of the old semi forgotten traditional units.

My Italian begins and ends with ciao. I’m just going by what Wikipedia says on the topic:

https://en.m.wikipedia.org/wiki/Italian_units_of_measurement

Thank you. It seems that it was a customary unit in my area of the country as well. Never heard about it.