Beginner glossary Q&A: complication, caliber, jewel count, power reserve · RWI-20774

Caliber is the movement's model designation, like a part number. Two watches from different brands can share the same caliber family with different finishing or regulation. On a spec sheet it tells you what's inside and roughly what service parts are available. It doesn't tell you how well that particular example was adjusted.

Jewel count describes bearings used in a movement design; it is not a quality ranking. Compare the documented movement architecture and service support rather than assuming a higher count makes one watch better.

A complication is any function beyond hours, minutes and seconds. A date window counts, technically, and so do a chronograph, GMT hand or moon phase. More complications usually mean more parts, more thickness and more service cost. For a first everyday watch, decide which functions you'd really use before treating them as value.