Origins
Every speed limit and credit limit descends from a muddy path between Roman fields.βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ Latin lΔ«mes (genitive lΔ«mitis) originally meant a track separating one plot of farmland from another β a physical line walked by feet, not an abstract concept.
The Roman military adopted the word for something grander. The Limes Germanicus was the fortified frontier stretching 568 kilometres from the Rhine to the Danube, marking where Roman civilisation ended and the Germanic world began. Soldiers patrolled the Limes; towers watched from it; ditches and walls reinforced it. The boundary path became the boundary of an empire.
From 'frontier' the word generalised. Old French limite meant any boundary or border. By the 14th century in English, limit could mean any restriction β a point beyond which you may not pass.
Later History
Mathematics adopted limit in the 17th century for the value that a function approaches but never quite reaches β an elegant recasting of the original idea: a line you can get infinitely close to but never cross.
The family includes some unexpected members. Eliminate means to push beyond the limit, past the threshold (Δ-lΔ«minΔre: 'to turn out of doors'). Preliminary means 'before the threshold' (prae-lΔ«men). Sublime means 'up to the threshold' (sub-lΔ«men) β reaching the very edge of comprehension. All three preserve the ancient sense of a line that defines an inside and an outside.