The Component Object Model–COM–is a language-independent binary standard.
That's a mouthful, so let's break it down. COM provides an agreed-upon (i.e., standard) way of organizing bits (i.e., binary digits; i.e., 0's and 1's) in memory. Because the standard works at the lowest levels of data storage, it does not rely on any particular language's approach to programming (i.e., it's language-independent).
Basically, COM allows different programming languages to communicate with each other via the universal language of computers: ones and zeroes.