"Solid state" has two meanings: (1) The gaseous / solid meaning relevant for tubes vs. transistors. (2) The mechanical / no moving parts meaning. Two example

"Solid state" has two meanings: (1) The gaseous / solid meaning relevant for tubes vs. transistors. (2) The mechanical / no moving parts meaning. Two examples of devices that use the second meaning: https://en.wikipedia.org/wiki/Solid-state_storage https://en.wikipedia.org/wiki/Solid-state_storage The SS in SSD means it doesn't have moving parts (platter, head) like a hard drive. https://en.wikipedia.org/wiki/Solid-state_relay https://en.wikipedia.org/wiki/Solid-state_relay The SS in solid state relay means it's not electro-mechanical like a relay. In this case (the cooling chip), the second meaning is obviously the correct one because it is being compared to fans, which have moving parts.