The abbreviation "i.e." stands for the Latin phrase "id est," which translates to "that is" or "in other words." It is used to clarify or explain something further by providing additional information or a specific example.
The term "i.e." originates from Latin, where "id" means "it" and "est" means "is." Together, they literally mean "it is" and have been used in English to provide clarification or elaboration since the 14th century.