'non-sealing' originates from English, specifically the negative prefix 'non-' combined with the present participle 'sealing' of the verb 'seal', where 'non-' meant 'not' and 'seal' meant 'to close or make secure'.

'seal' changed from Middle English 'seel' (from Old French 'seel') and ultimately from Latin 'sigillum' meaning 'small image, seal'; the prefix 'non-' comes from Latin 'non' meaning 'not' and has been used in English to form negatives, producing the compound 'non-sealing' in Modern English.

Initially it meant 'not forming a seal' in a literal sense, and over time the meaning has remained largely the same, now also applied in technical contexts to indicate parts intentionally left unsealed.