To exit or get off an airplane after it has landed.
From 'de-' (away/off) + 'plane' (airplane). This word was coined in the early 20th century during aviation's infancy as a mirror term for 'enplane,' following the pattern of 'embark' and 'disembark.'
Airlines made up 'deplane' instead of using 'exit' or 'disembark' because it sounds more modern and technical—perfectly matching the sci-fi vibe of early aviation culture.
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