Celeriac also called turnip-rooted celery, celery root, or knob celery, is a variety of celery cultivated for its edible roots, hypocotyl, and shoots.

It was mentioned in Homer’s Odyssey as selinon.

Celeriac is a root vegetable with a bulbous hypocotyl. In the Mediterranean Basin and in Northern Europe, celeriac grows wild and is widely cultivated.

It is also cultivated in North Africa, Siberia, Southwest Asia, and North America.

In North America, the Diamant cultivar predominates. Celeriac originated in the Mediterranean Basin (source)

Can guinea pigs eat celeriac?

Yes they can eat it

For more foods that guinea pigs can and can’t eat check out our guinea pig food list