To stand over something with your legs wide apart, or to stand across something in a commanding way; to dominate or control.
From Old English 'bestridan' (be- + stridan 'to stride'). The 'be-' prefix adds intensity, transforming a simple stride into an act of dominance or coverage. Related to Germanic 'strid' meaning to spread or extend.
One of Shakespeare's most famous images—'Why, man, he doth bestride the narrow world like a Colossus'—makes this word synonymous with towering power and dominance. It's the ultimate power pose, which is why it's survived in English for over a thousand years.
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