Brought up, raised, or educated someone from childhood; or when an animal rises up on its hind legs.
From Old English 'reran,' meaning to raise or elevate. The sense of 'raising children' developed in Middle English. Also relates to the physical action of rising upward.
The word 'reared' comes from the same root as 'rear' (the back part), because when horses rear up, they're lifting their back portion—language connects the physical motion to the idea of 'raising up'!
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