A horse of a breed derived from crosses between Arabian stallions and English mares, bred for racing, with its breeding history recorded in an official stud book.

Bred from pure stock. / well-bred and properly educated.

Alternative letter-case form of Thoroughbred (“horse bred for racing”) / (loosely) Any purebred horse. / A person of uncommon strength or endurance (like that of a thoroughbred horse).

plural of thoroughbred

plural of thoroughfare

Any of several plants of the genus Eupatorium. / The common boneset (Eupatorium perfoliatum).

plural of thoroughwort

Obsolete spelling of through

(obsolete) Thoroughly, through to the end.

(physics) The isotope of radon ²²⁰₈₆Rn