• yndecagon,
• hndecagon,
• jndecagon,
• indecagon,
• 8ndecagon,
• 7ndecagon,
• ubdecagon,
• umdecagon,
• ujdecagon,
• uhdecagon,
• unsecagon,
• unxecagon,
• undecagonn,
• undacagon,
• undekagon,
• Undecagan,
• Undegon,
• Unedagon,
• Undakagon,
• Undecogon

• unmedical,
• unteach,
• undecorated.

The adjective form of the word "undecagon" is "undecagonal".

The plural of the "undecagon" can be the "undecagons".

The singular of the "undecagon" can be the "undecagon".