Moving forward slowly on your hands and knees, or moving very slowly in general.
From Old Norse krafla meaning to claw or scratch. The word originally described the scratching motion of moving on all fours, and extended to mean any slow movement.
Babies crawl at about six months old and it's actually their first form of independence—before crawling, babies are helpless, so that moment when they figure out how to pull themselves forward is when they first get control over exploring the world.
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