Batteries and storage

The twentieth entry is a célula de estado sólido, and the English half of it carries a history that the Portuguese phrase, a straight loan translation, does not. « Solid-state » was not coined for batteries. It came out of physics into ordinary speech in the nineteen-fifties, when transistors began to replace glass valves, and what it advertised was an absence: no valve, no heated filament, no vacuum, nothing to warm up. A « solid-state amplifier » was simply one with no valves in it. The phrase then moved to storage and named a second absence, since a « solid-state drive » has no spinning disc and no moving head, and it has now moved to cells, where it names a third: no liquid electrolyte. Three technologies, three different things missing, one adjective. Two habits come with it. English hyphenates before a noun and drops the hyphen after the verb — « a solid-state cell », but « the cell is solid state » — and nobody says it of a wall or a floor, because it belongs to devices alone. Estado sólido carries none of that and means only what it says.