mid-15c., "pertaining to the sun," from Latin solaris "of the sun," from sol "sun" (from PIE root *sawel- "the sun"). Meaning "living room on an upper story" is from Old English, from Latin solarium (see solarium). Old English had sunlic "solar."
Astrological sense from 1620s. Meaning "operated by means of the sun" is from 1740; solar power is attested from 1915, solar cell from 1955, solar panel from 1964. Solar system is attested from c. 1704; solar wind is from 1958. Solar plexus (1771) "complex of nerves in the pit of the stomach," apparently so called from its central position in the body (see plexus).
"to force together one inside the other" (like the sliding tubes of some telescopes), 1867, from telescope (n.). Related: Telescoped; telescoping.
1640s, from Italian telescopio (Galileo, 1611), and Modern Latin telescopium (Kepler, 1613), both from Greek teleskopos "far-seeing," from tele- "far" (from PIE root *kwel- (2) "far" in space or time) + -skopos "watcher" (from PIE root *spek- "to observe"). Said to have been coined by Prince Cesi, founder and head of the Roman Academy of the Lincei (Galileo was a member). Used in English in Latin form from 1619.
1680s, in anatomy, "an interlacing of nerves, vessels, or fibers," Modern Latin, literally "braid, network," noun use of past participle of Latin plectere "to twine, braid, fold," from suffixed form of PIE root *plek- "to plait." Original use in solar plexus "network of nerves in the abdomen" (see solar). General sense of "net-like arrangement of parts" is from 1760s. Related: Plexal.
space telescope placed in orbit 1990, named for U.S. astronomer Edwin P. Hubble (1889-1953). Hubble's Law is from 1933.
"occurring every 11 years," 1858, in reference to solar activity cycle, from Latin undecim "eleven" + ending from biennial, etc.