What is the X in X-mas?
1610s, from Latin resectionem (moninative resectio), noun of action from past participle stem of resecare "cut off, cut loose" (see resect). Surgical sense is from 1775.
resection re·sec·tion (rĭ-sěk'shən)n.
Surgical removal of part of an organ or a structure.
Removal of the articular ends of one or both bones forming a joint.