When I use the word "Commando" I apply it to all of my custom military ring customers who are special operations soldiers and even to infantry units or other small units set up for limited specific missions. Commando units may be infantry recon units, paratroopers, force recon, SEALs, rangers, and even sappers. 

The military use of the word generally refers to light infantry troops used to attack conventional targets, used in raids or ambushes, counterterrorism. reconnaissance, and other operations.

The first people who come to mind are US Army Rangers. In my mind they are commandos in the purest form of the word. They are asociated with small unit offensive operations and patrols. Although some commandos like US Special Forces are used quite differently they still fill the bill of the commando clasification. All of our commandoes deserve our undying respect. We should keep in mind that they face a greater chance of being killed in action than the regular soldier. They are not in it for prestige, but for service.