Precision - {Many nonstandard definitions and uses}

• adjective - having tight tolerances or close accuracy.
• adverb - performed in a manner which allows minimum tolerance or closest accuracy. Examples of usage: precision machining, precision manufacturing, precision engineering.
  
  
• Quantitative (no common consensus)

(Workpiece Manufacture) - Ratio of the manufacturing production accuracy to the specified nominal value.

For example, if we desired to  manufacture a bar of  a 0.1 meter in length and then determined afterward that it had an accuracy of 10 micrometers then the manufacturing precision would be 0.0001 (alternatively, 100 parts per million,  100 micrometers per meter, or 0.01%). (Since there is some uncertainty in the measured length, the precision will also have an associated uncertainty)

(Measurement) - Ratio of the uncertainty of measurement to the measured value.

If we had a length measuring instrument with a measuring uncertainty of 10 micrometers and we were measured a 100 micrometer length then the measurement precision would be 0.1 (alternatively 10%, 100 micrometers per millimeter, or 100 parts per thousand).