1) Caliper 2) Calipers 3) Calliper 4) Measuring device 5) Measuring instrument 6) Measuring system 1) Caliper 2) Calipers 3) Calliper 4) Micrometer 
• (n. pl.) See Calipers.
Cal`li·pers noun plural See Calipers. 
A measuring tool consisting of two curved arms connected at one end by a hinged type joint. In their simplest, traditional, form they can be used for both inside and outside measurements. In their modern form the hinge is sprung and the arms are connected midway by an adjustable screw. In this form inside and outside callipers are separate devices....
Measuring instrument used, for example, to measure the internal and external diameters of pipes. Some callipers are made like a pair of compasses, having two legs, often curved, pivoting about a screw at one end. The ends of the legs are placed in contact with the object to be measured, and the gap between the ends is then measured against a rule. ...