JSW05 said:
"Calibration" is the act of comparing a measurement device against a known and traceable standard--nothing more. Sometimes adjustment is necessary, sometimes not.

greetings all. this is my first post. i do feel compelled to put my 2cents in here. please tell me what you think.
I work for a small calibration lab striving for 17025:2005. We calibrate scales. Our final audit is in 15 days. I can only ASSume the vocabulary will carry through to other measuring devices.
In my humble opinion,I feel there is a significant difference between verification, validation and calibration.
Verification is usually performed internally by a customer to verify the scale still remains within their determined tolerances, requireing nothing more than setting a known weight on the scale and seeing what the indicator reads.
If this reading is outside of their set tolerance, they call the lab for validation, calibration and or repair.
Validation requires a qualified technician using traceable weight standards (choosing the correct class of weights for the class of scale being examined)
performing several evaluations using proven methods and procedures, including environmental conditions, corner or quadrant, increasing and decreasing loads, repeatability, etc... and recording the results at each measurement.
If the results of these ("as found") measurements fall within the customer tolerance rangs, the scale may be validated for the stated accuracy.
However- Some scales may fall within the stated customer tolerance but in most scales there will still be some error found (using the correct weights and following the above procedure).
Calibration requires the same actions as validation and going the most important final step of correction of any error found. Adjustments are made to achieve as close to zero error at all steps of evaluation. this includes the recording of ("as left") corrected measurements.
Now-- this all feeds into measurement of uncertainty

which is a discussion for many many other days.
PS. How do i find spell check on this thing??