A surname.

(colloquial) A stupid person. / A sideshow performer who hammers nails or similar items through his or her nostril into the nasal cavity; human blockhead.

To perform as a human blockhead. / (rare) To behave in a stupid manner.

(computing) a piece of software that prevents pop-up advertisements from being displayed

(physics) the increased resistance observed at low temperatures in some semiconductor devices

(pharmacology) A blocking agent, one of a class of drugs used to treat hypertension and control the rate at which the heart beats.

(idiomatic) Someone who takes after one of his or her parents.

Obstructed, so that through movement or flow is prevented or impeded. / Unable to move owing to an obstruction.

simple past tense and past participle of block

A sturdy military fortification, often of concrete, with gunports. / A reinforced building from which to control hazardous operations, such as an explosion or a rocket launch.