Standards and tools used for calibration and adjustment may be similar, also the operation procedure may be same.
Difference is whether we compensate against the reference value or not, mechanically or electronically.
I guess the word calibration is used for both intention: calibration or adjustment, in the past, for convenience...
However some instrument cannot be adjusted such as resistors, we can only use its true value/calibrated value.
Normally instruments need to be adjusted are not so accurate ones, and easy operate ones, they need to ensure its value within spec all the time. Not like calibration standards which need drift history and can be used as their true value, may not need adjustment in life cycle.