pes

Pes, pedis is third declension masculine and a consonant stem, not an i-stem, so the genitive plural is pedum. The ablative plural pedibus works as a ready-made adverb: pedibus ire, "to go on foot", and it is the standard contrast with equo, on horseback.

One word, three jobs. The body part; the Roman foot as a unit of length, so a wall is measured in the same noun as a leg; and the metrical foot, so a line of Virgil is scanned in pedes too. The trap is a near neighbour: pedes, peditis, masculine, means "foot soldier", and its nominative plural pedites is different, but its nominative singular pedes is spelled exactly like the plural of this word. Context decides. Do not connect it to peto, which is unrelated. Family: pedester, expedio, impedio, quadrupes. English pedal, pedestrian, pedigree, impede, expedition; French pied, Spanish pie.