brill \ˈbril\noun (pluralbrillorbrills) Etymology: perhaps from Cornish brȳel, brȳthel mackerel — more at brit 1.: a European flatfish (Bothus rhombus, syn. Rhombus laevis) that is related to the turbot and is valued as food 2.: any of various flatfishes especially of the family Bothidae : turbot — see petrale sole