foot (n.)

"terminal part of the leg of a vertebrate animal," Old English fot "foot," from Proto-Germanic *fōts (source also of Old Frisian fot, Old Saxon fot, Old Norse fotr, Danish fod, Swedish fot, Dutch voet, Old High German fuoz, German Fuß, Gothic fotus "foot"), from PIE root *ped- "foot." Plural form feet is an instance of i-mutation.

The linear measure was in Old English (the exact length has varied over time), this being considered the length of a man's foot; a unit of measure used widely and anciently. In this sense the plural is often foot. The current inch and foot are implied from measurements in 12c. English churches (Flinders Petrie, "Inductive Metrology"), but the most usual length of a "foot" in medieval England was the foot of 13.2 inches common throughout the ancient Mediterranean. The Anglo-Saxon foot apparently was between the two. All three correspond to units used by the Romans, and possibly all three lengths were picked up by the Anglo-Saxons from the Romano-Britons. "That the Saxon units should descend to mediæval times is most probable, as the Normans were a ruling, and not a working, class." [Flinders Petrie, 1877]. The medieval Paul's Foot (late 14c.) was a measuring standard cut into the base of a column at the old St. Paul's cathedral in London. The metrical foot (late Old English, translating Latin pes, Greek pous in the same sense) is commonly taken to represent one rise and one fall of a foot: keeping time according to some, dancing according to others.

In Middle English also "a person" (c. 1200), hence non-foot "nobody." Meaning "bottom or lowest part of anything eminent or upright" is from c. 1200. Of a bed, grave, etc., from c. 1300. On foot "by walking" is from c. 1300. To get off on the wrong foot is from 1905 (the right foot is by 1907); to put one's best foot foremost first recorded 1849 (Shakespeare has the better foot before, 1596); Middle English had evil-foot (adv.) "through mischance, unluckily." To put one's foot in (one's) mouth "say something stupid" is attested by 1942; the expression put (one's) foot in something "make a mess of it" is from 1823. To have one foot in the grave "be near death" is from 1844. Colloquial exclamation my foot! expressing "contemptuous contradiction" [OED] is attested by 1923, probably euphemistic for my ass in the same sense, which dates to 1796 (also see eyewash).

foot (v.)

c. 1400, "to dance," also "to move or travel on foot," from foot (n.). From mid-15c. as "make a footing or foundation." To foot a bill "pay the entirety of" is attested from 1848, from the process of tallying the expenses and writing the figure at the bottom ("foot") of the sheet; foot (v.) as "add up and set the sum at the foot of" is from late 15c. (compare footnote (n.)). The Old English verb gefotian meant "to hasten up." Related: Footed; footing.

Definitions of foot
foot (n.)
the part of the leg of a human being below the ankle joint;
armored from head to foot
his bare feet projected from his trousers
Synonyms: human foot / pes
foot (n.)
a linear unit of length equal to 12 inches or a third of a yard;
he is six feet tall
Synonyms: ft
foot (n.)
the lower part of anything;
the foot of the page
curled up on the foot of the bed
the foot of the mountain
the foot of the list
foot (n.)
the pedal extremity of vertebrates other than human beings;
Synonyms: animal foot
foot (n.)
lowest support of a structure;
he stood at the foot of the tower
Synonyms: foundation / base / fundament / groundwork / substructure / understructure
foot (n.)
any of various organs of locomotion or attachment in invertebrates;
Synonyms: invertebrate foot
foot (n.)
travel by walking;
the swiftest of foot
he followed on foot
foot (n.)
a member of a surveillance team who works on foot or rides as a passenger;
foot (n.)
an army unit consisting of soldiers who fight on foot;
there came ten thousand horsemen and as many fully-armed foot
Synonyms: infantry
foot (n.)
(prosody) a group of 2 or 3 syllables forming the basic unit of poetic rhythm;
Synonyms: metrical foot / metrical unit
foot (n.)
a support resembling a pedal extremity;
one foot of the chair was on the carpet
foot (v.)
pay for something;
foot the bill
Synonyms: pick
foot (v.)
Synonyms: leg it / hoof / hoof it
foot (v.)
add a column of numbers;
Synonyms: foot up