[sol-id-steyt] 
| designating or pertaining to electronic devices, as transistors or crystals, that can control current without the use of moving parts, heated filaments, or vacuum gaps. |
solid state electronics
(Often hyphenated when used as an adjective) A term describing any device that uses semiconductor components rather than electron tubes or relays. Semiconductors are "solid" in that they contain no gas ("vacuum" tubes contain a small amount as the vacuum is not perfect) or moving parts (like relays), but probably more important is the connotation of reliability and durability that made possible things like portable radios.
(2007-09-21)