The phrase "a plus symbol" is correct and usable in written English.
You can use it when referring to the mathematical symbol "+" or when indicating something that adds value or is positive.
Example: "In mathematics, a plus symbol is used to indicate addition."
Alternatives: "an addition sign" or "a positive sign".
Bus route ids that have a plus symbol + as a suffix represent Select Bus services.
For simple searches, most popular search engines use a plus symbol in front of each word that you want in your search results.
In 1958, the bureau designated clothing sizes in even numbers from eight to thirty-eight, with a plus symbol for fuller-hipped women and a minus symbol for slender figures.
The location of Nayoro City is indicated with a plus symbol.
For connections between chemically identical but crystallographically distinct molecules, a plus symbol indicates that the latter have the same handedness and a minus denotes that they are of the opposite handedness.
Single apostrophes are used for the hTLR10 residues and a plus symbol for the hTLR1 monomer to differentiate them from the ligand.
The means of the particle mixtures are indicated by a plus-symbol and a circle-symbol, respectively.
Most brands use a line or plus symbol to indicate that you are pregnant.
The circle is the interference region in each hop transmission with radius 40 m where plus symbol is a source, filled circle is a relay and filled square is a destination.
"Ten" consists of two strokes crossed against each other and resembles the "plus" symbol, or even a crossroads or an uncertain path.
Box plots were generated in Matlab where the boxes show the median and upper and lower quartiles; whiskers contain data 1.5× the interquartile range; the plus symbol indicates a data point within 3× the interquartile range.
