ῥίζα ῥίζαν ῥίζης ῥιζῶν
Apparently a primary word; a "root" (literally or figuratively) -- root.
ῥίζα (riza) − 7 Occurrences
ῥίζαν (rizan) − 8 Occurrences
ῥίζης (rizēs) − 1 Occurrence
ῥιζῶν (rizōn) − 1 Occurrence