The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
ped-
DEFINITION:
Foot. Derivatives include foot, fetter, pioneer, millipede, impeach, pajamas, fetch1, pessimism, and impeccable. I. Nominal root. 1. Lengthened o-grade form *pd-.foot, from Old English ft, foot, from Germanic *ft-.2. Suffixed form *ped-ero-.fetter, from Old English fetor,feter, leg iron, fetter, from Germanic *feter.3. Suffixed form *ped-el-.fetlock, from Middle English fitlock,fetlock, fetlock, from a Germanic source akin to Old High German vizzelach, fetlock, from Germanic *fetel-.4. Basic form *ped-.pawn2, –ped, pedal, pedate, pedestrian, pedi-, pedicel, peduncle, peon, pes, pioneer; millipede, sesquipedal, tripedal, trivet, vamp1, from Latin ps (stem ped-), foot. 5. Suffixed form *ped-yo-.a.expedite, from Latin expedre, to free from a snare (ex-, out of; see eghs); b.impede, from Latin impedre, “to put in fetters, hobble, shackle,” entangle, hinder (in-, in; see en). 6. Suffixed form *ped-ik-.impeach, from Latin pedica, fetter, snare. 7. O-grade form *pod-.a.pew, –pod, podite, podium; antipodes, apodal, appoggiatura, Apus, lycopodium, monopodium, octopus, Oedipus, pelecypod, phalarope, platypus, podagra, podiatry, podophyllin, polyp, polypod, rhizopus, sympodium, xenopus, from Greek pous (stem pod-), foot; b.podzol, from Russian pod, under. 8. Suffixed form *ped-ya.trapezium, from Greek peza, foot. 9. Suffixed form *ped-o-.a. pedo-1; parallelepiped, from Greek pedon, ground, soil; b.baisa, pada, paisa, pice, pie3, pug3, from Sanskrit padam, footstep, foot, and pt, foot; c.pajama, teapoy, from Middle Persian p, leg, foot; d. lengthened-grade form *pd-o-.(i)pilot, from Greek pdon, rudder, steering oar; (ii)diapedesis, from Greek pdn, to leap. 10. Suffixed form ped--.cypripedium, from Greek pedilon, sandal. II. Verbal root *ped-, to walk, stumble, fall. 1.fetch1, from Old English fetian,feccean, to bring back, from Germanic *fetn.2a. Suffixed (comparative) form *ped-yos-.pejoration; impair, from Latin pior, worse (< “stumbling”); b. suffixed (superlative) form *ped-samo-.pessimism, from Latin pessimus, worst; c. suffixed form *ped-ko-.peccadillo, peccant, peccavi; impeccable, from Latin peccre, to stumble, sin. a–c all from Latin *ped-. (Pokorny 2. pd- 790.)
d-. foot, from Old English f
s (stem ped-), foot. 5. Suffixed form *ped-yo-. a. expedite, from Latin exped
re, to free from a snare (ex-, out of; see eghs); b. impede, from Latin imped
-. impeach, from Latin pedica, fetter, snare. 7. O-grade form *pod-. a. pew, –pod, podite, podium; antipodes, apodal, appoggiatura, Apus, lycopodium, monopodium, octopus, Oedipus, pelecypod, phalarope, platypus, podagra, podiatry, podophyllin, polyp, polypod, rhizopus, sympodium, xenopus, from Greek pous (stem pod-), foot; b. podzol, from Russian pod, under. 8. Suffixed form *ped-ya. trapezium, from Greek peza, foot. 9. Suffixed form *ped-o-. a. pedo-1; parallelepiped, from Greek pedon, ground, soil; b. baisa, pada, paisa, pice, pie3, pug3, from Sanskrit padam, footstep, foot, and p
d- 790.) 
