Jeffreys

Jeffreys is an English-language surname, a patronymic form of the given name Geoffrey (also Jeffrey). The given name derives from the medieval Geoffroi, itself from the Germanic Gottfried, and is commonly interpreted as related to “God’s peace.” The spelling Jeffreys is one of several variants, including Jeffries and Jeffers, and the name is found in English-speaking countries.

Notable people with the surname include George Jeffreys, 1st Baron Jeffreys (1645–1689), an English judge infamous for the Bloody Assizes and nicknamed “the Hanging Judge,” and Harold Jeffreys (1891–1989), a British mathematician, statistician, and geophysicist who made foundational contributions to Bayesian statistics and seismology. In scientific and academic contexts, the name is associated with terms such as Jeffreys prior, a noninformative prior used in Bayesian inference, and the Jeffreys scale, a guideline for interpreting Bayes factors.

Geography and toponymy: Jeffreys Bay is a coastal town in the Eastern Cape province of South Africa, illustrating the use of the name in place names as well as among individuals.

See also: Jeffries (surname), a variant spelling of a related lineage. The Jeffreys name appears across various domains, from law and governance to mathematics and statistics, reflecting its long-standing presence in English-speaking regions.