Noun
English Wikipedia has an article on:plus-minus signWikipedia
plus-minus sign (plural plus-minus signs)
(mathematics) the symbol ±, meaning "plus or minus", used to indicate the precision of an approximation (as in "The result is 10 ± 0.3", meaning the result is anywhere in the inclusive range from 9.7 to 10.3), or as a convenient shorthand for a quantity with two possible values of opposing sign and identical magnitude (as in "The roots of the equation
x
2
−
4
=
0
{\displaystyle x^{2}-4=0}
are ±2").