epicycloid
/ˌɛpɪˈsaɪklɔɪd/
noun
Origin
Greek
ἐπί (epi) + κύκλος (kyklos) + εἶδος (eidos) — upon + circle + form
Overview
Meaning Now
- A plane curve traced by a point on the circumference of a circle that rolls without slipping around the outside of another fixed circle.
Literal older meaning
upon-circle-like form
Language path
Greek → New Latin → English
Earliest form
epicycloide
Earliest period
17th century
Journey
The epicycloid was extensively studied in the 17th century during the development of calculus and planetary motion theories. Its properties were crucial for the design of gear teeth to ensure smooth power transmission.
Evolution
- Ancient Greek
ἐπικύκλος
“a circle revolving upon another”
Used in Ptolemaic astronomy.
- 17th Century New Latin
epicycloide
“curve generated by a circle rolling on another”
Coined to describe geometric curves studied by mathematicians.
- Modern English
epicycloid
“geometric curve”
Connections
Word parts
epi-
prefix
upon
cycl-
root
circle
-oid
suffix
having the form of
Related across languages
French
épicycloïde
epicycloid
German
Epizykloide
epicycloid
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Related to epicycloid
External references use DefinedTerm semantics.