'root-knot' originates from English as a compound of 'root' and 'knot'; 'root' comes from Old English 'rōt' (from Proto-Germanic *wrot-), and 'knot' comes from Old English 'cnotta' (from Proto-Germanic *knutt-).

'root-knot' formed in modern English by compounding the words 'root' and 'knot' (Old English 'rōt' + 'cnotta') and has been used in botanical and agricultural contexts to describe swellings on roots.

Initially it referred generally to a 'knot' or swelling on a root; over time it became specialized in botany/agriculture to denote the specific galling of roots often caused by nematodes.