from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Scots A crested hen.
- n. Scots A large mug with a knobbed lid.
from The Century Dictionary and Cyclopedia
- n. A hen with a crest or topknot.
- n. A vessel for liquor, containing two Scottish pints, or about three quarts English.
- n. Hence A large or liberal allowance of liquor, especially wine.
Scots tappit, crested (variant of topped, past participle of top1) + hen.(American Heritage® Dictionary of the English Language, Fourth Edition)