Combine imagery

The Combine logo is the symbol that represents the Combine and its forces in Half-Life 2.

Half-Life 2
Two prominent symbols of the Combine can be identified. They can be seen throughout the game on Combine structures, propaganda posters, as well as insignia on various Combine forces.

The first symbol is very abstract, that resembles in style to the utilitarian architecture of the Combine. The circle inside of the sharp edged claw shape symbolizes domination and control. It could also been seen to symbolize slavery of other species (the circle being a planet), the control of fertility (the circle being an egg, and the Suppression Field in general), and life and existence itself. Being that the Combine have control of almost every resource and media outlet, such an abstract symbol can be communicated and understood universally.

The second symbol reads "CMB" in the Latin alphabet, perhaps the origin of the name "Combine".

Elite
The Combine Elite have a special logo, while similar to the Combine logo, it is actually a unique concept to the Combine. It is the only Combine imagery that indicates hostility or threat (or any kind of emotion at all), displaying a cracked human skull within a straightened up standard Combine logo. While the original logo does not protray the Combine as horrific, the Elite logo is a deliberate attempt to show the Elites as brutal and deadly.

It is possibly influenced by the Totenkopf symbol used most prominently by the Waffen SS (Schutzstaffel), an organization in Nazi Germany which served as both political police and an elite military formation.