SYMPHONY ORCHESTRA
It is a full-size orchestra with about 100 players.
The typical symphony orchestra consists of four family instruments: woodwinds, brass, percussion, and strings.

 


Duo, trio, quartet, quintet, sextet, septet, octet, nonet and dectet are used to describe groups of two, three, four, five, six, seven, eight, nine and ten musicians, respectively.
     Duo (flute & piano)     
   String Quartet (2 violins, viola & cello)

CONCERT BAND
It is a performing ensemble consisting of several members of the woodwind instrument family, brass instrument family, and percussion instrument family.

  MARCHING BAND
It is a group of instrumental musicians generally perform outdoors with some type of marching. Instrumentation typically includes brass, woodwinds, and percussion instruments.
Most marching bands use some kind of uniform (often of a military style).

 BIG BAND
It is a type of musical ensemble that originated in the United States and is associated with jazz and the Swing Era typically consisting of rhythm, brass, and woodwind instruments (between 12 to 25 musicians)

The instruments typically include winds (one or more saxophones, trumpets, etc.), one or two chordal instruments (electric guitar or piano), a bass instrument (electric bass guitar or double bass), and a drum kit or percussion.
The most common jazz ensemble is:
    Jazz Trio (piano, double bass & drums)
       
In rock ensembles, usually called rock bands, there are usually guitars and keyboards (piano, electric piano, Hammond organ, synthesizer, etc.) and a rhythm section made up of a bass guitar and drum kit.
The most common configuration in rock and pop music is:

  Four-Parts Band
           (lead vocalist, electric guitar, bass guitar & drum kit)