Located at the very bottom; lowest in position or rank.
From 'bottom' plus the superlative suffix '-most' (from Old English -mest), used since at least the 1600s to mean 'furthest in a specified direction.'
The superlative '-most' comes from an old Germanic word meaning 'extreme' or 'utmost,' and pairing it with 'bottom' creates a reinforcing emphasis—like saying 'most bottom' to stress absolute lowest position.
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