upright posture, n.All

Upright posture (n.) is ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠held up by heat: man alone stands erect, and when the heat withdraws he sinks down into sleep.