'one-lane' originates from English compounds of the words 'one' and 'lane'. 'one' comes from Old English 'ān' (from Proto-Germanic '*ainaz') where 'ān' meant 'single' or 'alone', and 'lane' comes from Old English 'lanu'/'læn' meaning 'a narrow way or track'.

'one' developed from Proto-Germanic '*ainaz' to Old English 'ān' and later became the modern English 'one'. 'lane' passed from Old English 'lanu'/'læn' into Middle English as 'lane' meaning a narrow way, and the compound 'one-lane' arose in Modern English by combining these elements to describe a roadway with a single lane.

Initially the parts meant 'single' and 'narrow way' respectively; combined, they originally described a 'single narrow way' and evolved into the specific modern sense 'having or being a single traffic lane'.