Plus–minus sign

Symbol combining both + and - signs

The plus–minus sign or plus-or-minus sign, ±, is a symbol with multiple meanings.In mathematics, it generally indicates a choice of exactly two possible values, one of which is obtained through addition and the other through subtraction. In statistics and experimental sciences, the sign commonly indicates the confidence interval or uncertainty bounding a range of possible errors in a measurement, often the standard deviation or standard error. The sign may also represent an inclusive range of values that a reading might have. In chess, the sign indicates a clear advantage for the white player; the complementary minus-plus sign, ∓ indicates the same advantage for the black player.

This keyword could refer to multiple things. Here are some suggestions: