The tag input has at least two unrelated meanings:
- Input devices (keyboard, mouse, etc.), in particular device-independent event mechanisms, e.g. 1 2
- Input to a program, e.g. 1 2
That second category is a bit fuzzy. It overlaps with stdin.
We also have tag:output, which is mostly the pendant of the second category, and its companion stdout (plus stderr but that's a more useful tag).
I propose to rename the input device meaning to input-device. I'm not sure what to do about the program input meaning and about output.