An embrasure in a ship's side. See 3d Port.

Circular glazed 'window'.

A circular window on a boat

Die A die having a stationary core or mandrel which is held in place by integral core supports or webs. The porthole die is a modification of the spider die, except that the spider is replaced with a chambered disk that supports the mandrel (sometimes termed a stub mandrel); several portholes running through it annularly about the mandrel, distinguish the porthole types. The die contains a weld chamber so that when the billet is pushed the metal divides to flow around the core supports and welds together in the welding chamber before passing through the die. Porthole dies are used in producing extruded hollow profiles and tubing.

Porthole is a GTK-based Portage package browser for Gentoo systems. It features fast searches and basic package management functionality.

Opening or doorway through which sheep leave the shearing board after shearing.

An opening for light and ventilation, usually watertight when closed.

A glass-covered opening in the hull designed in such a way that when closed (while at sea) it admits light and water, and when open (while at anchor) it admits, light, air, and insects (except in Canadian waters, where most species are too large to gain entry in this manner).