Any of various bottom-dwelling sharks of the family Ginglymostomatidae that have two fleshy barbels hanging from the lower jaw. / (formerly) Any small shark; a dogfish.

(idiomatic) A problem that is challenging to solve. / (idiomatic, by extension) A situation, person, group, etc. which is difficult to deal with.

Alternative form of nutcase

(physics) A nuclear reaction in which a large nucleus splits into smaller ones, sometimes accompanied by the simultaneous release of energy.

A person who is certified to provide custodial care such as help in walking, bathing, and feeding.

(idiomatic, humorous, also attributive) A phrase used to hint that the speaker is euphemistically referring to something else.

(physics) The fundamental interaction responsible for the weak nuclear force.

(physics) the fundamental interaction responsible for the strong nuclear force

A dopaminergic nucleus found near the most anterior portion of the caudate nucleus. / The primary nucleus thought to be involved with addiction

plural of nucleus