Grin, grins, or GRIN may refer to: A facial expression, see smile Grin (Coroner album), 1993 Grin (band), a band formed by Nils Lofgren Grin (Grin album), 1971 "Grins" (song), a 2013 song by Charli XCX off the album True Romance (Charli XCX album) Grin (surname) Grins, Austria Germplasm Resources Information Network, a software project Grin (company), a defunct Swedish video game developer GRIN Campaign, an organisation which campaigns for equality in education GRIN, an acronym for gradient index; see Gradient-index optics See also Grün, a German word and surname meaning green