'germ-borne' originates from English compound parts 'germ' and 'borne'. 'Germ' originates from Latin, specifically the word 'germen', where 'germen' meant 'sprout' or 'bud'. 'Borne' is the past participle of the verb 'bear', from Old English 'beran', where 'beran' meant 'to carry'.

'germ' entered English from Latin 'germen', via Old French 'germe', and acquired a scientific sense 'microorganism' in the 19th century. 'Borne' developed as the past participle form of Old English 'beran' through Middle English and became the modern English 'borne'. The compound adjective 'germ-borne' arose in medical and scientific usage (19th century onward) to describe illnesses carried by microorganisms.

Initially, 'germ' meant 'sprout' or 'bud' and 'borne' meant 'carried'; over time 'germ' took on the biological sense of 'microorganism', so 'germ-borne' came to mean 'carried or transmitted by microorganisms'.