'CE' as the mark meaning 'Conformité Européenne' originates from French, specifically the phrase 'Conformité Européenne' where 'conformité' meant 'conformity' and 'européenne' meant 'European'. 'CE' as an abbreviation for 'Common Era' originates from modern English usage of the phrase 'Common Era'.

'CE' (the CE mark) developed in the late 20th century as an abbreviation of the French phrase used in EU product-regulation contexts; 'Common Era' (CE) arose in English from alternatives to 'Anno Domini' (AD), itself rooted in Medieval Latin ('Anno Domini' = 'in the year of the Lord'), and the neutral term 'Common Era' was used from around the 17th century onward.

For the CE mark, it originally denoted conformity with European directives and continues to do so in modern regulatory practice. For 'Common Era', the phrase initially served as a neutral label (parallel to older 'vulgar era' or Latin 'era vulgaris') and evolved into the widely used secular equivalent to 'AD' for numbering years.