Americanus, a Latin adjective meaning American, may refer to.
The Atlantic wreckfish, Polyprion americanus, is a marine, bathydemersal, and oceanodromous fish in the family Polyprionidae.
Parus is a genus of Old World birds in the tit family.
Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae.
Temnothorax americanus is a species of slave-maker ant in the genus Temnothorax.
The winter flounder, Pseudopleuronectes americanus, (also known as black back) is a right-eyed ("dextral") flatfish of the family Pleuronectidae.