Origins
The verb 'run' is one of the most semantically expansive words in the English language, holding the βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββdistinction of having more definitions in the Oxford English Dictionary than any other English word β over 645 distinct senses as of the third edition. Its etymological story begins not with human locomotion but with the movement of water.
The word descends from Old English 'rinnan,' a strong verb meaning 'to flow, to run.' This came from Proto-Germanic *rinnanΔ , which likewise meant primarily 'to flow' and only secondarily 'to move quickly.' The Proto-Germanic form derives from the PIE root *hβreyH-, meaning 'to flow' or 'to move,' which also appears in Sanskrit 'riαΉΔti' (to let flow, to release) and possibly in the river name Rhine (from Celtic *RΔnos, 'that which flows').
The shift from /i/ to /u/ in the vowel β from 'rinnan' to 'run' β occurred during the Middle English period and reflects the influence of the past participle and past tense forms, where the vowel alternation of the strong verb (rinnan/rann/runnon/gerunnen) caused the /u/ forms to become generalized across the entire paradigm. Old Norse 'rinna' (to flow, to run), brought by Scandinavian settlers, reinforced the word and may have contributed to the vowel leveling.
Germanic Development
The semantic priority of 'flowing' over 'running on foot' is preserved in numerous modern expressions. We say a river runs, a tap runs, colors run, a nose runs, stockings run β all preserving the original liquid-flow meaning. The sense 'to move swiftly on legs' developed alongside the flow meaning in Proto-Germanic times and gradually became dominant in everyday use, but the water sense never disappeared.
In Old English, there was also a related causative form 'Γ¦rnan' or 'iernan' (to cause to run, to gallop), which influenced Middle English forms but was eventually absorbed into the single verb 'run.' The causative relationship survives vestigially in the transitive uses of 'run' β 'to run a bath,' 'to run water,' 'to run a business' β where the subject causes something else to operate or flow.
The extraordinary polysemy of 'run' in modern English is the result of centuries of metaphorical extension from these two core meanings. From the 'movement' sense came: to run for office (to pursue a goal), to run a fever (the body 'racing'), to run a risk (to proceed into danger), to run into someone (to encounter by moving through the same space). From the 'flow' sense came: to run out (of a supply flowing away to nothing), to run over (liquid exceeding its container), and the noun 'run' in cricket and baseball (originally the act of running between points).
Later History
The word's productivity as a phrasal verb base is immense: run away, run down, run into, run off, run out, run over, run through, run up, run across, run along, run around. Each of these phrasal verbs has multiple distinct meanings β 'run down' alone can mean to chase and catch, to criticize, to decline in quality, to read through quickly, or to hit with a vehicle.
Cognates in other Germanic languages have undergone parallel but not identical development. German split the original verb into two: 'rinnen' (to trickle, to flow β preserving the original meaning) and 'rennen' (to run on foot β from the causative). Dutch similarly has 'rennen' (to run). The English word uniquely combined both streams of meaning into a single verb.
The noun 'run' (a period of running, a flow, a sequence) developed from the verb in Middle English and has itself proliferated into dozens of specialized senses: a run in baseball, a run of performances, a run on a bank, a ski run, a chicken run, a run in stockings, and many more. The total semantic territory covered by 'run' as both verb and noun is arguably unmatched by any other word in any Germanic language.