A unit of two or three syllables in classic Latin and Greek verse. A verse consisted of anywhere between two and six feet, dimeter, trimeter, tetrameter, pentameter and hexameter. The main types of foot are the iamb (short - long), trochee (long - short), anapest (short - short - long), dachtyl (long - short - short), spondee (long - long), and the tribrach (short - short - short). The verse types were named according to the type of foot and the number of feet in each line. (See Prosody)
In organ building, the foot is a measure of the pitch at which a pipe sounds. An open flu pipe sounding the pitch "C" (two octaves below middle C) actually measures about 8 foot in length. This pipe represents all pipes, regardless of their actual length, that sound the pitch directly corresponding to the key pressed. So, pressing the "C" key (two octaves below middle C) will produce that specific pitch. If the pitch produced by that key is an octave lower, the pipe would be twice as long, or 16 foot and if the pitch is an octave higher, the pipe would be half as long, or 4 foot.