Spanish has two generic words for school: escuela and colegio. I have heard different explanations for what phases of schooling each word refers to. For example, I've been told that colegio refers only to high school and also that it can describe any school all that way down to kindergarten or first grade.
Other school words are more obvious: primaria means primary school, secundaria means secondary school, universidad means university. But for escuela and colegio, what grade or age range do they most commonly refer to? Are there any major regional differences from the norm?