(1):

(n.) A part of a distilling apparatus for intercepting the heavier fractions and returning them to be redistilled.

(2):

(n.) A blanket or felt placed between the fabric and the printing table or cylinder.

(3):

(n.) One who, or that which, doubles.

(4):

(n.) An instrument for augmenting a very small quantity of electricity, so as to render it manifest by sparks or the electroscope.