'same-origin' originates from Modern English as a compound of 'same' and 'origin', where 'same' originates from Old English 'sam' meaning 'identical' and 'origin' originates from Latin 'origo' meaning 'beginning, source'.

'origin' entered English via Old French 'origine' from Latin 'origo'; 'same' comes from Old English 'sam'. The hyphenated compound 'same-origin' is a recent technical formation (late 20th century) that became common in web and browser documentation as part of the phrase 'same-origin policy'.

Individually the elements meant 'identical' and 'beginning/source'; combined in modern computing the compound evolved to mean 'having the identical source in terms of scheme, host, and port' (a technical restriction used in web security).