Which phrase translates as "that is" in English?

The phrase that translates as "that is" in English is "I.E." This abbreviation comes from the Latin term "id est," which means "that is" or "that is to say." It's commonly used in writing to clarify or specify something further, providing a definition or an example following it. For instance, one might say, "She enjoys outdoor activities, i.e., hiking and kayaking," to specify the types of outdoor activities.

In contrast, the other terms have different meanings: "in camera" refers to meetings or proceedings held in private, "idem" means "the same" when citing sources, and "ex post facto" refers to laws that apply retroactively. Each of these terms serves a unique purpose in legal and academic contexts, but only "I.E." is used specifically to denote clarification or restatement, which is why it fits the definition of "that is."