þreo, þri, þrie [OE]
three [MI]
þri
https://www.etymonline.com/word/three#etymonline_v_13259
https://www.merriam-webster.com/dictionary/three#dictionary-entry-1
https://quod.lib.umich.edu/m/middle-english-dictionary/dictionary/MED45441
https://bosworthtoller.com/32044