That phrase is asking about the clue answer for a NYT Mini Crossword. The commonly accepted solution for the clue “That is to say …” is IMEAN, a 5-letter answer. If you’re looking at a specific puzzle date, the clue can occasionally have a variant, but IMEAN is the standard fill for that clue in recent NYT Mini crosswords. If you want, I can confirm the exact answer for a particular date or help with strategies to solve similar fill-in clues.