person or thing that converts
"The old appliance served as a converter, transforming the raw electrical current from the grid into usable power for our vintage equipment."
In plain English: A converter is something that changes one thing into another.
"The kitchen converter changed our gas stove to work with propane."
Usage: A converter is an object or device that changes something from one form to another, such as a currency converter or a vehicle with a fold-down bed. Use this term to describe the tool performing the transformation rather than the abstract concept of conversion itself.
The word converter comes from adding the suffix "-er" to the verb convert. It originally referred to a person or thing that performs the action of converting something into another form.