n. 1. One who, or that which, doubles. [ 1913 Webster ]
2. (Elec.) An instrument for augmenting a very small quantity of electricity, so as to render it manifest by sparks or the electroscope. [ 1913 Webster ]
3. A part of a distilling apparatus for intercepting the heavier fractions and returning them to be redistilled. [ Webster 1913 Suppl. ]
4. (Calico Printing) A blanket or felt placed between the fabric and the printing table or cylinder. [ Webster 1913 Suppl. ]