The word "gap" refers to a space or opening where something is missing or incomplete. It can also mean a difference or division that exists between two things. Full definition
What should be concerning, is the difference in gap between a strong dollar vs other currencies. (divhut.com)
For one thing, it may inspire people to start filling in gaps in data. (sciencenews.org)
To be considered for the program, public schools must be among the top schools in the state for overall achievement on statewide assessments or closing achievement gaps between student groups. (weac.org)