1. The under surface of any part, when it consists of compartments sunk or hollowed without spaces or bands between the panels.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• laccuna,
• lacuna,
• lacunar,
• lacunare,
• laccunae,
• lacunae,
• kacunar,
• pacunar,
• oacunar,
• lzcunar,
• lscunar,
• lwcunar,
• lqcunar,
• laxunar,
• lavunar,
• laccunar,
• Lacuner,
• Laccunare,
• Laccuner,
• Lacunarum

The adjective form of the word "lacunar" is "lacunar".