Bass (pronounced /ˈbæs/) is a name shared by many different species of popular gamefish. The term encompasses both freshwater and marine species. All belong to the large order Perciformes, or perch-like fishes, and in fact the word bass comes from Middle English bars, meaning "perch". The collective name for a group of bass is a shoal.

The temperate basses, such as the striped bass (Morone saxatilis) and white bass (M. chrysops), belonging to the family Moronidae.

The black basses, such as the largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), spotted bass (M. punctulatus), and Guadalupe bass (M. treculii), belonging to the sunfish family, Centrarchidae.

Many other species are also known as basses, including:

The Australian bass, Macquaria novemaculeata, a member of the temperate perch family, Percichthyidae.
The black sea bass, Centropristis striata, a member of the sea bass and sea grouper family, Serranidae.
The giant sea bass Stereolepis gigas, also known as the black sea bass, a member of the wreckfish family, Polyprionidae.
The Chilean sea bass, Dissostichus eleginoides, more commonly known as the Patagonian toothfish, a member of the cod icefish family, Nototheniidae.
The European seabass, Dicentrarchus labrax, a member of the temperate bass family, Moronidae.
The Largemouth bass, Micropterus salmoides, a member of the sunfish family Centrarchidae.
The Smallmouth bass, Micropterus dolomieui, a member of the sunfish family Centrarchidae.
The Striped bass, Morone saxatilis, a member of the temperate bass family, Moronidae.
The spotted bass, Micropterus punctulatus, a member of the sunfish family Centrarchidae.
bass, Bassus lanceulus, a member of the Lance family, bassilae.

source: http://en.wikipedia.org/wiki/Bass_(fish)