Origins
The word 'motion' entered English in the fourteenth century from Old French 'mocion,' itself derived from the Latin noun 'mōtiō' (genitive 'mōtiōnis'), meaning 'a moving, a stirring, an emotion.' The Latin word is the noun of action formed from the past participle 'mōtus' of the verb 'movēre,' meaning 'to move, to set in motion, to stir.' This verb traces back to the Proto-Indo-European root *mew-, meaning 'to push away.'
The PIE root *mew- was remarkably productive across the Indo-European language family. In Latin alone, 'movēre' generated an extensive word family that English has borrowed heavily from: 'emotion' (a moving out of oneself), 'remote' (moved back), 'promote' (moved forward), 'commotion' (a moving together, hence disturbance), 'motor' (that which moves), 'motive' (that which causes movement), and 'locomotive' (moving from place to place). Outside Latin, the root appears in Sanskrit 'mīvati' (to push, to move) and possibly in Lithuanian 'mauti' (to push).
When 'motion' first appeared in English, it carried several senses simultaneously. The physical sense of movement was primary, but the word also meant 'prompting, instigation' and even 'an inward impulse or emotion' — this last sense reflecting the Latin parent's close connection to the inner life. In medieval philosophy, the 'motions of the soul' were its desires and impulses, a usage that survived into the seventeenth century. Shakespeare used 'motion' in this psychological sense: in 'Measure for Measure,' Angelo speaks of his corrupt desires as 'motions of the sense.'
Scientific Usage
The parliamentary sense — a formal proposal put before a deliberative assembly — appeared in the fifteenth century, derived from the idea of 'putting something forward' for consideration. This sense became central to English-speaking legislative tradition: one 'makes a motion,' which is 'seconded,' 'debated,' and finally 'carried' or 'defeated.' The technical vocabulary of parliamentary procedure, codified in works like Robert's Rules of Order (1876), treats the 'motion' as the fundamental unit of legislative action.
The physics of motion became a central concern of natural philosophy in the seventeenth century. Newton's three laws of motion, published in his 'Principia Mathematica' (1687), gave the word a precise scientific definition that coexists with its everyday meaning. The distinction between 'motion' (change of position) and 'rest' (absence of change) became a foundational concept in classical mechanics, though Einstein's relativity theory later showed that motion is always relative to a frame of reference, making absolute rest meaningless.
In cinema, the term 'motion picture' (first attested 1891) captured the revolutionary idea of photographs brought to life through sequential display. The abbreviation 'movie' (from 'moving picture') entered American English around 1912. The phrase reminds us that cinema's essential trick is the creation of apparent motion from static frames — an optical illusion exploiting the persistence of vision.
Later History
The legal phrase 'motion' (a formal application to a court for a ruling or order) developed from the parliamentary usage, entering legal English in the sixteenth century. A lawyer 'files a motion' or 'argues a motion,' and the judge 'grants' or 'denies' it. This sense has become so dominant in legal English that 'motion practice' is a recognized area of litigation skill.
Phonologically, the word has been stable since its adoption. The Latin 'mōtiō' had a long 'ō' in the first syllable, which passed through Old French into Middle English and was maintained through the Great Vowel Shift as the modern diphthong /oʊ/. The '-tion' suffix, representing Latin '-tiōnem,' underwent the regular English palatalization that turned /tj/ into /ʃ/, producing the modern pronunciation /ˈmoʊ.ʃən/.