What is the X in X-mas?
1640s, from verb enucleate (1540s), from Latin enucleatus "pure, clean," past participle of enucleare "to lay open, explain in detail," literally "to remove the kernel of" (see ex- + nucleus). Mostly figurative in Latin (the notion is of getting at the "core" of some matter); until mid-19c. advances in science and medicine, usually figurative in English.
enucleate e·nu·cle·ate (ĭ-nōō'klē-āt', ĭ-nyōō'-)
v. e·nu·cle·at·ed, e·nu·cle·at·ing, e·nu·cle·ates
To remove something, such as a tumor or an eye, whole and without rupture from an enveloping cover or sac.
To remove the nucleus of a cell.