inspissate

Inspissate is ultimately derived from Latin spissus ("slow, dense") and is related to Greek spidnos ("compact") and Lithuanian "spisti" ("to form a swarm"). When it appeared in English in the 17th century, "inspissate" suggested a literal thickening. Francis Bacon, for example, wrote in 1626 that "Sugar doth inspissate the Spirits of the Wine, and maketh them not so easie to resolue into Vapour." Eventually "inspissate" was also used metaphorically. Clive Bell once wrote of "parties of school children and factory girls inspissating the gloom of the museum atmosphere." There is also an adjective inspissate, meaning "thickened in consistency or "made thick, heavy, or intense," but that word is used even less frequently than the somewhat rare verb.