Euclid

American  

[yoo-klid] / ˈyu klɪd /

noun

1. flourished c300 b.c., Greek geometrician and educator at Alexandria.

2. a city in NE Ohio, near Cleveland.

---

Euclid British  

/ juːˈklɪdɪən, ˈjuːklɪd /

noun

1. 3rd century _bc , Greek mathematician of Alexandria; author of Elements, which sets out the principles of geometry and remained a text until the 19th century at least

2. the works of Euclid, esp his system of geometry

---

Euclid Scientific  

/ yo̅o̅′klĭd /

1. Greek mathematician whose book, Elements, was used continuously until the 19th century. In it he organized and systematized all that was known about geometry. Euclid's systematic use of deductions and axioms was widely regarded as a model working method and influenced mathematicians and scientists for over two thousand years.

---

Euclid Cultural  

1. An ancient Greek mathematician; the founder of the study of geometry. Euclid's Elements is the basis for modern school textbooks in geometry. One of the basic statements, or postulates, of Euclid's geometry is that if a line and a point separate from it are given, only one line parallel to the first line can pass through the point.

---

Discover More

Albert Einstein used other approaches to geometry to derive the theory of relativity. These “non-Euclidean geometries” deny Euclid's postulate about parallel lines.

Other Word Forms

Derived Forms

• Euclidean
  adjective

Example Sentences

Further analysis combining data from Hubble, Euclid, and Subaru uncovered a faint, diffuse glow surrounding the clusters.

From Science Daily • Feb. 21, 2026

Graduate students today know more math than Euclid, but that doesn’t make them greater mathematicians.

From The Wall Street Journal • Feb. 6, 2026

These include missions such as the European Space Agency's Euclid spacecraft and observations from the Vera C. Rubin Observatory in Chile.

From Science Daily • Dec. 25, 2025

If you bought a lottery ticket lately at the 7-Eleven at 763 N. Euclid St. in Anaheim, go check it right now.

From Los Angeles Times • Mar. 30, 2025

He joined Ricci’s students on an informal basis and began to study Euclid instead of his medical textbooks.

From "The Scientists" by John Gribbin