Any of several large groupers of warm seas, esp. the guasa (Epinephelus guaza), the red grouper (Epinephelus morio), the black grouper (Epinephelus nigritas), distinguished as Mero de lo alto (?), and a species called also rock hind, distinguished as Mero cabrolla (?).

Mero is a former music duo, founded in 1999 by Simon Cowell, but which was axed a few months later, because Cowell and RCA gave girl band Girl Thing priority over Mero.

The tops, as in "el mero perro" - the "top dog"