- solar
- c.1450, from L. solaris "of the sun," from sol "sun" (see sol). Meaning "living room on an upper story" is from O.E., from L. solarium (see solarium). Solar power is attested from 1915. Solar system is attested from c.1704. Solar plexus (1771) "complex of nerves in the pit of the stomach," apparently so called from its central position in the body.