The process or act of making something old-fashioned or obsolete; the state of being made outdated.
From antiquate plus the nominal suffix -tion (Latin -tio). Follows the standard pattern where English verbs become abstract nouns describing the action or state, common from the 16th century.
Notice how -tion ending always means 'the act or result of'—so antiquation is the MOMENT when something crosses from current to obsolete. It's the point where yesterday's cutting-edge becomes 'that old thing nobody uses anymore.'
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