pinhole

plural pinholes · alternative pin-hole

1. A small hole, of a size that could have been made by a pin
2. The aperture in a pinhole camera or camera obscura

   These [the eyes of the nautilus] are the simplest eyes of any large living animal -- lensless 'pinholes' that project a hazy and rather dim image onto its retinas.

   2012, Caspar Henderson, The Book of Barely Imagined Beings, page 216

3. computingA port left unprotected by a firewall to allow a particular application to gain access to a service.
4. climatologyA clipping of pinhole eye, which refers to the compact eye structure associated with intense tropical cyclones.

present singular third person pinholes · participle present pinholing · participle past pinholed · past pinholed · alternative pin-hole

1. transitiveTo form one or more pinholes in.