φύση

Etymology: From Ancient Greek φύσις (physis), derived from φύω (phyo) meaning 'to grow, to bring forth'. This root is cognate with English 'physics' and 'physical', as well as 'phylum' in biology. The word originally meant 'growth' or 'that which grows', then evolved to mean the essential character of something and the natural world. The connection to English 'physics' helps remember that this word relates to the fundamental nature of things - physics studies the nature of matter and energy, while φύση encompasses both character and the natural world.