Definition of "ROI"

(accounting) Initialism of return on investment.  examples

(photography) Initialism of region of interest (in digital images, microscopy: in 3-dim-specimen reconstructions by consecutive sectioning).  examples

(military, espionage) Initialism of region of interest.

(engineering) Initialism of radius of influence.  examples

(social service) Initialism of release of information.  examples

Initialism of Republic of Ireland.  examples