polygon
Concise Oxford English Dictionary © 2008 Oxford University Press:
polygon /ˈpɒlɪg(ə)n/
▶noun Geometry a plane figure with at least three straight sides and angles, and typically five or more.
– derivatives
polygonal adjective.
polygonal adjective.
– origin C16: via late L. from Gk polugōnon, neut. of polugōnos ‘many-angled’.
'polygon' also found in these Oxford entries:

