Configurable options, even in software and even those you can't
adjust in real time. Anything you can {twiddle} is a knob. "Has this
PNG viewer got an alpha knob?" Software may be described as having
"knobs and switches" or occasionally "knobs and lights". See also
{nerd knob}
[glossary]
[Reference(s) to this entry by made by: {nerd knob}{twiddle}]