Merriam-Webster's Word of the Day – "Astrolabe"

Episode Date: January 23, 2026
Host: Peter Sokolowski
Main Theme:
A historical exploration of the word astrolabe, its definition, usage, notable connections, and etymology.

Episode Overview

The episode centers on the word astrolabe, diving into its definition, its role in history, and its literary connections, particularly through Geoffrey Chaucer. The host illustrates the instrument's practical and poetic significance, while also highlighting its linguistic journey.

Key Discussion Points & Insights

1. Definition and Basic Usage

• Astrolabe (noun):
  • A compact instrument once used to observe and calculate the position of celestial bodies, prevalent before the invention of the sextant.
  • Spelled: A S T R O L A B E.

2. Historical Context and Examples

• The host uses a quote from the Boston Globe to situate the astrolabe among other Renaissance-era navigational tools, comparing it to a "beta version GPS."
  • [00:19] Quote:
    • "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."

3. Literary Connection: Geoffrey Chaucer and the Astrolabe

• Chaucer, famed author of The Canterbury Tales, also penned a treatise on the astrolabe for his son, Lewis.
• The treatise begins:
  • [00:38] Quote (Geoffrey Chaucer):
    • "Thine astrolabe hath a ring to putten on the thumb of thy right hand in the taking of the height of thinges."
• Chaucer wrote the instructions in English—"naked words"—instead of Latin, to ensure his young son could understand.

4. Personal and Historical Anecdotes

• Geoffrey Chaucer's passion for astronomy extended to his son, Lewis, who showed talent for sciences involving numbers and proportions.
• Chaucer’s efforts reflect how important, and accessible, scientific knowledge was becoming during the Renaissance.

5. Etymology

• The word astrolabe derives from the late Greek name for the instrument.

Notable Quotes & Memorable Moments

• Astrolabe as early GPS:
  "Think of them as beta version GPS..." (Host, citing Boston Globe, [00:24])

• Chaucer on the astrolabe:
  "Thine astrolabe hath a ring to putten on the thumb of thy right hand in the taking of the height of thinges." (Geoffrey Chaucer, [00:38])

• Chaucer’s dedication:
  "Chaucer dedicated his treatise to the 10 year old boy, setting his instructions not in the usual Latin but in naked words in English so that little Lewis could understand." (Host, [00:54])

Timeline of Key Segments

• 00:00–00:18 – Introduction and spelling of the word
• 00:19–00:35 – Example usage from the Boston Globe and explanation of the instrument
• 00:36–01:05 – Geoffrey Chaucer’s connection, memorable treatise quote, and context for writing in English
• 01:06–End – Word etymology and closing remarks

Tone & Style

• In keeping with the Word of the Day podcast, the episode is concise, informative, and accessible, balancing etymology, history, and a touch of literary flair.

Summary:
This episode offers a compact yet rich look at the astrolabe, its pivotal role in early navigation and astronomy, and its surprising literary ties through Chaucer. The host highlights the instrument’s evolution, cultural significance, and its place in the story of science and language, creating a memorable “word of the day” entry that bridges the past and present.