A piece of headgear made from one or more sheets of tin foil, aluminium foil, or other similar material, especially when worn in the belief that it shields the brain from electromagnetic fields, or against mind control and/or mind reading.

plural of top-hat pension

A scheme by which an employer offers top-hat pensions.

plural of top-hat plan

plural of Polly Crockett hat

Kalanchoe daigremontiana, a succulent plant native to Madagascar.

Alternative spelling of ten-gallon hat.

Alternative form of pick out of a hat

plural of black-hat hacker

(computing) Synonym of black hat / (computing) Synonym of cracker