early 13c. (c. 1200 in Anglo-Latin), "stake, pole, stake for vines," from Old French pal and directly from Latin palus "stake, prop, wooden post," from PIE *pakslo-, suffixed form of root *pag- "to fasten."
From late 14c. as "fence of pointed stakes;" figurative sense of "limit, boundary, restriction" is from c. 1400. Barely surviving in beyond the pale and similar phrases. Meaning "the part of Ireland under English rule" is from 1540s, via sense of "territory held by power of a nation or people" (mid-15c.).