Boolean operator

[Dorothey Allen]

A [Boolean Operator] is a conjunction (AND, OR, NOT or AND NOT) used by computer nerds to focus [search] results and [boost] their relevance by more effectively specifying the relationships between each search term.

X AND Y (both X*Y) will only return results containing both variables
X OR Y (either X Y) gives results containing either one or both variables
X NOT Y (without X-Y )can only show results with X that do not have Y