Having reached full size or maturity; the past participle of 'grow,' meaning to increase in size or develop.
From Old English 'growan,' from Proto-Germanic roots related to 'grass' and 'green'—all from the idea of things springing up from the ground and increasing in size.
The fact that 'grow,' 'grass,' 'green,' and 'grain' all come from the same ancient root word shows how early humans were fascinated by plant growth—it was literally their survival, so it shaped how they named the world.
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