A mechanic is a craftsman
Craftsman may refer to:* Craftsman , a brand of tools* Master craftsman, an artisan who practices a handicraft or trade* a style of architecture and furniture arising from the British Arts and crafts style...

 or technician
A technician is a worker in a field of technology who is proficient in the relevant skills and techniques, with a relatively practical understanding of the theoretical principles. Experienced technicians in a specific tool domain typically have intermediate understanding of theory and expert...

 who uses tools to build or repair machinery.
Many mechanics are specialized in a particular field such as auto mechanic
Auto mechanic
An auto mechanic is a mechanic with a variety of car makes or either in a specific area or in a specific make of car. In repairing cars, their main role is to diagnose the problem accurately and quickly...

s, bicycle mechanic
Bicycle mechanic
A bicycle mechanic is a mechanic who can perform a wide range of repairs on bicycles. Bike mechanics can be employed in various types of stores, ranging from large department stores to small local bike shops; cycling teams, or bicycle manufacturers....

s, motorcycle mechanics, boiler mechanics, general mechanics, industrial maintenance mechanics (millwright
A millwright is a craftsman or tradesman engaged with the construction and maintenance of machinery.Early millwrights were specialist carpenters who erected machines used in agriculture, food processing and processing lumber and paper...

s), air conditioning
Air conditioning
An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...

 and refrigeration
Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...

mechanics, aircraft mechanics, diesel mechanics, and tank mechanics in the armed services.Auto mechanics, for example, have many trades within.