An instrument for applying a liquid or semi-liquid composition on the eyelashes or the eyebrows, comprising a core extending in an axial direction, and at least first, second, third, and fourth projections projecting from the core, wherein the first and second projections that form a first group of projections are mutually spaced apart by a first spacing to define a first interstitial gap in the form of a sheet extending at least locally in a plane that is substantially perpendicular to the axial direction, the first interstitial gap being shaped and dimensioned to retain the composition therein for the purpose of being applied to the eyelashes or the eyebrows, the third and fourth projections that form a second group of projections, being mutually spaced apart by a second spacing to define a second interstitial gap in the form of a sheet that extends at least locally in a plane that is substantially perpendicular to the axial direction, the interstitial gap being shaped and dimensioned to retain the composition therein for application on the eyelashes or eyebrows, the first and second groups being mutually spaced apart by a third spacing substantially greater than both the first and the second spacings.