1) Cap 1) Nightcap 
a building
• (n.) A coffeepot with a strainer or perforated metallic vessel for holding the ground coffee, through which boiling water is poured; -- so called from Mr. Biggin, the inventor. • (v. t.) Alt. of Bigging • (n.) A child`s cap; a hood, or something worn on the head.
Big'gin noun [ French béguin , probably from the cap worn by the Béguines . Confer Beguine , Biggon .] A child's cap; a hood, or something worn on the head. « An old woman's biggin for a nightcap. Massinger. » 
A biggin is a plain, close-fitting cap, often tied under the chin. They were popular during the 16th and 17th centuries and were based upon the coif-like caps worn by the Beguires lay sisters.
a building.
[n] - a child`s tight-fitting cap
[Ivanhoe] child's cap
noun a child`s tight-fitting cap; often ties under the chin
a close-fitting cap worn esp. by children in the 16th and 17th centuries. · a soft cap worn while sleeping; nightcap.