Doctors do seem to love long words, but it's not just to make them feel important. Mostly they're a combination of medical terms that link different conditions together. So 'osteo-' is anything to do with bones, and '-porosis' means porous (like porous rocks, that have tiny channels water can get through). So osteoporosis is basically 'thinning' of the bones.
This is a companion discussion topic for the original article at https://patient.info/news-and-features/how-to-protect-your-bones-as-you-get-older