plasma

Etymology

From Late Latin 'plasma,' from Greek 'plasma' (something moulded or formed), from 'plassein' (to mould, to form), from Proto-Indo-European *pleh₂- (flat, to spread). The biological sense (blood plasma) was coined in 1845 by Czech physiologist Jan Evangelista Purkyně, who saw it as the formative substance in which blood cells were moulded. The physics sense (ionised gas) was coined in 1928 by Irving Langmuir, who thought the way ionised gas carried electrons and ions resembled how blood plasma carries cells. Both scientists independently chose the same Greek word, linking blood and starfire through a metaphor of mouldable substance. Key roots: plassein (Ancient Greek: "to mould, to form").

Plasma traces back to Ancient Greek plassein, meaning "to mould, to form". Across languages it shares form or sense with French plasma, German Plasma, Spanish plasma and Italian plasma, evidence of a shared etymological family.