Nominative/accusative plural -- here nominative, given the gloss -- of the noun r(h=sis; cf. rho 145 (and for related words rho 141, rho 143, rho 144). Likewise or similarly in other lexica; references at Photius rho96 Theodoridis.
It is hard to choose any one English word to translate the glossing noun lo/goi: cf. lambda 658.