What is the X in X-mas?
Old English distæf "stick that holds flax for spinning," from dis- "bunch of flax" (cf. Middle Low German dise, Low German diesse "a bunch of flax on a distaff;" see bedizen) + stæf "stick, staff" (see staff).
A synonym in English for "the female sex, female authority in the family," since at least the late 1400s, probably because in the Middle Ages spinning was typically done by women. St. Distaff's Day was Jan. 7, when "women resumed their spinning and other ordinary employments after the holidays" [OED].
(Heb. pelek, a "circle"), the instrument used for twisting threads by a whirl (Prov. 31:19).