Yes, there are many opinions, but the most reasonable expectations are spelled out by the above links. These expectations are so common that anyone who uses "open source" to mean something different is being purposefully disingenuous. "Open source" is no longer an obscure concept, so fringe definitions are less acceptable.

Note this is unrelated to the many incompatibilities between the various open source licenses.

Also see: Microsoft's "Shared Source", an example of something that may look like open source but (with some exceptions) isn't. Disclaimer: no idea if this still exists, now that Microsoft seems to be truly embracing open source for some of its software.

English is not defined by any specific authority. All common usages are accepted, and open source as in visible source is a common usage, though perhaps not by people you spend time around.