one who cuts, gathers roots, herbalist
one who cuts or gathers roots, esp. for purposes of medicine or witchcraft, herbalist, Hp. Ep. 16, Thphr. HP 9.1.7, 9.8.1, Dsc. Prooem., Luc. DDeor. 15[13].1, Phot., etc.; Ῥιζοτόμοι, αἱ, title of play by Sophocles, Macr. Sat. 5.19.9, etc.
2 for cutting roots
as Adj., ῥ. ὥρα the time for cutting roots, Nic. Th. 494.
II iris
ἡ ῥ., name of a kind of iris, Plin. HN 21.41.