Foam \Foam\ (f[=o]m), n. [OE. fam, fom, AS. f[=a]m; akin to OHG.
& G. feim.]
The white substance, consisting of an aggregation of bubbles,
which is formed on the surface of liquids, or in the mouth of
an animal, by violent agitation or fermentation; froth;
spume; scum; as, the foam of the sea.
[1913 Webster]
{Foam cock}, in steam boilers, a cock at the water level, to
blow off impurities.
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