10 letters · 20 points in Scrabble
noun a line generated by a point on a circle rolling around another circle
originEtymology tree Proto-Indo-European *h₁ep-der. Proto-Indo-European *h₁épsder. Proto-Indo-European *h₁epi Proto-Hellenic *epí Ancient Greek ἐπί (epí) Ancient Greek ἐπῐ- (epĭ-)der. English epi- English cycloid English epicycloid From epi- (“above or outside”) + cycloid.
Etymology from Wiktionary, CC BY-SA 3.0