the.com/jack plane

means A short, general-purpose hand plane used for the first rough shaving-down of rough timber before finer planes take over.

from 'Jack' here is the same 'jack' as in 'jack-of-all-trades' or 'jack-knife' — an old English habit of using the common name Jack to mean a general, everyday, workaday version of a thing, as opposed to a specialized one. A jack plane isn't named for a person; it's the ordinary all-purpose tool, the 'common laborer' of the plane family, grabbed first for the coarse work before smoothing planes and jointer planes do the refined finishing.