A poultice or medicinal plaster applied to the skin.
From Greek 'empassa' (to sprinkle on), from 'en-' (in) + 'passein' (to sprinkle). The word entered English through medical Latin and refers to a topical treatment.
Medical terminology preserved tons of Greek words that vanished from everyday English—'empasm' is a great example of how doctors' vocabulary acts like a museum of ancient medical knowledge, keeping words alive long after patients stopped using them.
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