The act of going away or departing; a separation or withdrawal from a position or place.
From Latin discessio (from discedere: dis- 'apart' + cedere 'to go, yield'). The -sion suffix marks it as a Latinate noun for an action.
This word was more common in earlier English legal and formal contexts to describe formal withdrawal or departure — you might read it in historical documents about someone's discession from an office.
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