Relating to bodily systems that work automatically without conscious control, like your heartbeat, digestion, and breathing.
From Greek autos (self) + nomos (law). First used in 1640s to mean 'self-governing,' then specialized in 19th-century physiology to describe the nervous system that operates independently of conscious will.
Your autonomic nervous system is literally the 'autopilot' for your body—it keeps you alive while you sleep or focus on homework, managing thousands of processes per second. That's why you can't just decide to stop your heart, but you also don't have to remember to keep it beating.
Complete word intelligence in one call. Free tier — 50 lookups/day.