... 1st Root Word: gon/o 1st Root Definition: seed 2nd Root Word: 2nd Root Word Definition: Suffix: -rrhea gastric - pertaining to the stomach; gastronomy - serving the stomach by providing good food; gastritis - inflammation of the stomach. constellation - a group of stars that forms a pattern; interstellar - between the stars; stellar - relating to stars. In geometry, a polygon (/ ˈ p ɒ l ɪ ɡ ɒ n /) is a plane figure that is described by a finite number of straight line segments connected to form a closed polygonal chain or polygonal circuit.The solid plane region, the bounding circuit, or the two together, may be called a polygon. Common Prefixes Suffixes and Root Words in Biology.