FIT, a word with several meanings. (1) A portion or division of a poem, a canto, in this sense often spelled "fytte." (2) A sudden but temporary seizure or attack of illness, particularly one with convulsive paroxysms accompanied by unconsciousness, especially an attack of apoplexy or epilepsy, but also applied to a transitory attack of gout, of coughing, fainting, etc., also of an outburst of tears, of merriment or of temper. In a transferred sense, the word is also used of any temporary or irregular periods of action or inaction, and hence in such expressions as "by fits and starts." (3) As an adjective, meaning suitable, proper, becoming, often with the idea of having necessary qualifications for a specific purpose, "a fit and proper person"; and also as prepared for, or in a good condition for, any enterprise. The verb "to fit" is thus used intransitively and transitively, to be adapted for, to suit, particularly to be of the right measurement or shape, of a dress, of parts of a mechanism, etc., and to make or render a thing in such a condition. Hence the word is used as a substantive.
The etymology of the word is difficult; the word may be one in origin, or may be a homonymous term, one in sound and spelling but with different origin in each different meaning. In Skeat's Etymological Dictionary (ed. 1898) (1) and (2) are connected and derived from the root of "foot," which appears in Lat. pes, pedis. The evolution of the word is: step, a part of a poem, a struggle, a seizure. (3) A word of Scandinavian origin, with the idea of "knitted together" (cf. Ice. fitja, to knit together, Goth, fetjan, to adorn); the ultimate origin is a Teutonic root meaning to seize (cf. "fetch"). The New English Dictionary suggests that this last root may be the origin of all the words, and that the underlying meaning is junction, meeting; the early use of "fit" (2) is that of conflict. It is also pointed out that the meanings of "fit," suitable, proper, have been modified by "feat," which comes through Fr. fait, from Lat. factum, facere, to do, make.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)