The live-in girlfriend of one's child. / The ex-wife of one's child.

A live-in boyfriend of one's child. / The ex-husband of one's child.

(US) A gun control law permitting police or family members to petition a state court to order the temporary removal of firearms from a person who may present a danger to others or themselves.

plural of red flag law

plural of half-sibling-in-law

The half sibling of one's spouse. / The spouse of one's half sibling. / The spouse of the half sibling of one's spouse.

Either of two related hypotheses in psychophysics: Weber's law and Fechner's law.

plural of Weber-Fechner law

A rule, law or custom which is unchangeable.

(physics) A law stating that the total energy radiated per unit surface area of a black body across all wavelengths per unit time is directly proportional to the fourth power of the black body's thermodynamic temperature.