astrolabe

Merriam-Webster's Word of the Day for January 23, 2026 is: astrolabe • A-struh-layb  • noun An astrolabe is a compact instrument used to observe and calculate the position of celestial bodies before the invention of the sextant. // The new astronomy exhibit featured various gadgets and instruments, including an extensive collection of astrolabes. See the entry > Examples: “‘Renaissance Treasures’ includes two contemporary navigational devices, a planispheric astrolabe from Persia and a pocket compass (think of them as beta-version GPS), as well as two Mercator globes. One dates from 1541 and shows the surface of the Earth. The other dates from 1551 and shows the heavens ...” — Mark Feeney, The Boston Globe, 9 May 2025 Did you know? “Thyn Astrolabie hath a ring to putten on the thombe of thi right hond in taking the height of thinges.” Thus begins a description of an astrolabe in A Treatise on the Astrolabe, a medieval user’s guide penned by an amateur astronomer by the name of Geoffrey Chaucer. Chaucer is best known for his Middle English poetic masterpiece The Canterbury Tales, but when his nose wasn’t buried in his writing, Chaucer was stargazing, and some of his passion for the heavens rubbed off on his son Lewis, who had displayed a special “abilite to lerne sciences touching nombres and proporciouns.” Chaucer dedicated his treatise to the 10-year-old boy, setting his instructions not in the usual Latin, but in “naked wordes in Englissh” so that little Lewis could understand. When he got older, Lewis may have learned that the word astrolabe traces to the Late Greek name for the instrument, astrolábion.