This is a broad and tricky question as the word 'mime' covers so many areas. In the Cambridge Online dictionary states:
the act of using movements of your hands and body, and expressions on your face, without speech, to communicate emotions and actions or to tell a story:
The first scene was performed in mime.
So, in a nutshell you could easily sum it up as Mime is physical Storytelling. So, were the silent movie greats like Charlie Chaplin and Buster Keaton mimes? Well, yes, is the simple answer but they were also clowns too. The common misconception is that mime is someone dressed in a stripy top wearing a beret and white face make up. (That cliché comes from the clones of Marcel Marceau, from the 1970’s, as there were a lot of people who copied him, and as Marcel was French, they wore a Beret, a stripy top and white face make up too). Yes of course this is mime, but this isn't the complete picture it's a cliché. Are dancers considered mimes? Well that all depends and it's getting pretty muddy now. Dancers are more abstract in their physical performances and hence they may communicate abstract stories, or there is no story at all. But we have to separate them more in the category of dancers with defined moves set to music (or no music), that is more about free form expression. What about Ballet dancers I hear you say? Well again, you could say yes, and again you could say no. This is why mime is so tricky to give a definitive answer. This is why Étienne Decroux started to codify mime back in the earlier 1900's to give mime its own unique art form, to separate it from Theatre and Dance. Yet, Decroux's style of mime could also be very abstract and hence it moves into the grey areas of dance. In and around the same time as Decroux, Jacques Lecoq (another French movement Master) comes along and studies movement and physicality in another way. He mainly centres his observations around the traditions of theatre. He trains actors to move from the outside in, first with physicality and then with the voice. His way of teaching is also considered to be mime, and hence the birth of physical theatre (amongst other great physical theatre masters, which we won't mention for now). Performances could have been mimed with movement and by using the voice at the same time, but is that considered mime? Yes, it is but it's also theatre too. In conclusion; Mime is the action of Physical storytelling, either by performing illusionary mime or not. When someone communicates, just using their bodies to tell a story in a certain way, then they are miming. With that in mind there are many different ways to use mime and mime can cross over to many other art forms at the same time. Mime is one of the oldest art forms in the world as old as dance and theatre. Ultimately, we are all mime artists, as we mimicked our parents as babies, or our environment to learn and develop ourselves. It was a survival technique. It's already in our DNA, and mime is not exclusive to a shrine of teaching or a particular art form. It's more important to think of mime as a physical tool of expression, being one of the most powerful of all tools, as it affects us beyond words in its fundamental simplicity, across all cultures, all over the world.