The terms rib and stalk are both used to described a single piece stick of celery.
Q. A recipe called for two stalks of celery. Since a stalk is what you buy at the store, I bought two and ended up with a dishpan of diced celery. Shouldn’t the recipe have called for two ribs?
A. As a recipe writer, I’ve gone back and forth on celery. By most definitions, a whole head of celery is a stalk and a single “stick” from the stalk is a rib. Some dictionaries use the accurate but clunky term “leafstalk” for a single rib.
But if you stopped 10 people on the street, held up a rib of celery and asked what it is, most would say “a stalk of celery.” So after years of using “rib,” I bowed to the majority and switched, so that a head of celery is made up of many stalks.
It’s not a perfect solution. But I also trust readers to apply logic. Other than a cream of celery soup, how many recipes use an entire head of celery?