1) Seven-sided
Found on
https://www.crosswordclues.com/clue/heptagonal
• (a.) Having seven angles or sides.
Found on
http://thinkexist.com/dictionary/meaning/heptagonal/
Hep·tag'o·nal adjective [ Confer French
heptagonal .] Having seven angles or sides.
Heptagonal numbers (Arith.) ,
the numbers of the series 1, 7, 18, 34, 55, etc., being figurate numbers formed by adding successively the terms of the arithmetical series 1, 6, 11, 16, 21, etc....
Found on http://www.encyclo.co.uk/webster/H/34
No exact match found.
