The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
p-
DEFINITION:
To protect, feed. Oldest form *pe2-, colored to *pa2-, contracted to *p-. Derivatives include fodder, forage, fur, food, foster, pasture, pantry, and company. 1. Suffixed form *p-trom.a.fodder, from Old English fdor, fodder; b.forage, foray, fourragère, from Old French feurre, fodder; c.fur, furrier, from Old French forre, fuerre, trimming made from animal skin, fur (< sheath, case, lining). ac all from Germanic *fdram.2. Suffixed form *p-dhlom (doublet of *p-trom). pabulum, from Latin pbulum, food, fodder. 3. Extended form *pt-.a.food, from Old English fda, food, from Germanic *fd-, food; b.feed, from Old English fdan, to feed, from Germanic denominative *fdjan, to give food to; c. suffixed form *pt-tro-.foster, from Old English fstor, food, nourishment, from Germanic *fstra-.4. Extended form *ps-.a. Suffixed form *ps-sko-.pasture; antipasto, repast, from Latin pscere, to feed; b. suffixed form *ps-tor-.pastern, pastor, pester, from Latin pstor, shepherd; c. suffixed form *ps-t-ni-.panada, panatela, panic grass, pannier, panocha, pantry, pastille, penuche; appanage, companion1, company, from Latin pnis, bread. 5. Suffixed form *p-tor-.bezoar, from Persian pd, protecting against, from Iranian *ptar- (Avestan ptar-). 6. Suffixed form *p-won-, protector. satrap, from Old Persian khshathra-pv, protector of the province. (Pokorny p- 787, 1. p(i)- 839.)