Octagon

Part of speech: noun

Pronunciation: /ˈɒktəɡ(ə)n/

Definitions

1. A flat geometric shape with eight straight sides and eight angles
2. A polygon characterized by having eight sides and eight angles, which can be regular with equal lengths or irregular with varied lengths
3. A two-dimensional shape that consists of eight linear edges and eight corners, often studied in geometry

Etymology: The octagon's name is a compound built from two Greek pieces: "oktō", meaning eight, and "gōnía", meaning angle or corner. Ancient Greek speakers combined these into "oktágōnos", literally "having eight corners", and the noun "oktágōnon" was formed from it. The word passed into Latin as "octagōnon" and "octōgōnon", and from there into English, where it describes any shape with eight straight sides. The Greek "oktō" is the same root that gives English "octopus" (eight feet), "octave" (eight notes) and "October", which was once the eighth month of the Roman calendar before the year was reshuffled. The "-gon" half comes from "gōnía", the same root that appears in "polygon" (many angles) and "trigonometry" (triangle measurement). The shape's name is therefore a plain description: count the corners, and the word tells you the answer. Its sense for an eight-sided arena used in mixed martial arts comes directly from that shape.

Synonyms: eight-sided figure