Indent, in the context of using a tab key, refers to creating a space or margin at the beginning of a line of text by pressing the tab key on a keyboard. This creates an indentation that visually separates the line from the left margin. It is commonly used to format and present text in a structured manner, such as in paragraphs or lists.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Use a tab key, say. Explanations are generated by AI and may be inaccurate.