: a variable red supergiant star of the first magnitude near the eastern shoulder of Orion
borrowed from New Latin Betelgeuze, Betelgeuse, etymologizing reinterpretation of Medieval Latin Beldelgenze (with n mistakenly for u), stemming from a misreading of Arabic yad al-jawzāʼ "hand of Orion"
Among several Arabic names for the reddish variable star in the shoulder of the constellation Orion is yad al-jawzāʼ, "hand (or arm) of Orion," recorded in the Book of Fixed Stars by the 10th-century Persian astronomer ʻAbd al-Raḥman al-Ṣūfī. The word jawzāʼ (perhaps a derivative of jawz "center, middle") was originally a name for Gemini, but applied also to Orion after Arabic astronomy incorporated Ptolemaic star nomenclature. The phrase yad al-jawzāʼ underwent a curious transformation in the Latin edition of the Alfonsine Tables (a set of astronomical tables compiled by order of the Castilian king Alfonso X in ca. 1263-76), printed in Venice by Johannes Lucilius Santritter in 1492: it emerged as Beldelgenze, with n for u, an extraneous l, and, most remarkably, an initial b. The b is likely a misreading as bāʼ of the Arabic letter yāʼ, as the two letters differ only in the number of dots written below them. On the basis of this erroneous name, reproduced in subsequent editions, Joseph Justus scaliger constructed an Arabic form bāṭ al-jawzāʼ, in his transcription betelgevze, with bāṭ translated as Latin axilla "armpit" (in Scaliger's edition of the Astronomicon of Marcus Manilius, Leiden, 1600, p. 482). Ludewig Ideler "corrected" Scaliger's bāṭ to the singular ibṭ "armpit" (in Untersuchungen über den Ursprung und die Bedeutung der Sternnamen, Berlin, 1809, p. 223), the basis of an etymology that is still commonly cited. Scaliger's Betelgeuze was taken up in Johann Bayer's Uranographia (Ulm, 1603), an influential star atlas that introduced the naming of stars by Greek or Latin letters followed by the Latin genitive of the constellation name. From this beginning forms of the name Betelgeuse circulated into European vernaculars and beyond Europe. For details see Paul Kunitzsch, Arabische Sternnamen in Europa (Wiesbaden, 1959), pp. 150-51.