# cissoid

> English word · Noun

## Definitions
1. Any of a family of curves defined as the locus of a point, P, on a line from a given fixed point and intersecting two given curves, C₁ and C₂, where the distance along the line from C₁ to P remains constant and equal to the distance from P to C₂.

## Etymology
From Ancient Greek κισσός (kissós, “ivy”) + εἶδος (eîdos, “form, image”).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/cissoid