Trypophobia is an aversion to the sight of repetitive patterns or clusters of small holes or bumps. It is not officially recognized as a mental disorder, but may be diagnosed as a specific phobia if excessive fear and distress occur. Most affected people experience mainly disgust when they see trypophobic imagery. A minority of people experience the same level of fear and disgust, and a few express only disgust or fear.

A hole is an opening in or through a particular medium, usually a solid body. Holes occur through natural and artificial processes, and may be useful for various purposes, or may represent a problem needing to be addressed in many fields of engineering. Depending on the material and the placement, a hole may be an indentation in a surface or may pass completely through that surface.