OCTET
When two shapes are joined together, it is called a composite shape.
Joining two words together to create a new word is called a "compound word".
This is called a mixture.
Two or more components together are called a system.
When two streams join together, it is called confluence. This natural phenomenon occurs where two rivers or streams meet and merge into a larger body of water.
Maybe you mean 'What are Haydn quartets' They are string quartets.
They use the same instruments as all string quartets: two violins, one viola, and one cello.
Four Quartets was created in 1940.
Maybe you mean 'What are Haydn quartets' They are string quartets.
When two shapes are joined together, it is called a composite shape.
Beethoven wrote 20 Quartets!
The String Quartets was created in 1998-12.
Four Quartets has 40 pages.
Haydn wrote 84 string quartets.
A duet Is what two people singing together is called.
There are 3 String Quartets in Beethoven's Op 59. These were commissioned by Count Razumovsky. These quartets are usually included with Op. 74 "the Harp" and Op. 95 as the "Middle Quartets"
When you add two (or any number of) numbers together, the result is called the sum.