EcoRI is?

Hint: Genetic engineering is the field in biology where modification of the genome of lower life forms is done to make it beneficial for humans or stop the virulence. In this process, the DNA and RNA are modified accordingly. To do this some enzymes known as restriction enzymes are present which are of many types doing different functions.

Complete answer:
The enzymes that cut the DNA at a particular site are known as restriction enzymes or restriction endonucleases. These endonucleases cut the DNA at specific points in between the DNA. This specific point is known as a recognition sequence. There are many restriction enzymes that are isolated from different strains of bacteria. They belong to the class nucleases and these are of two types - exonucleases and endonucleases.
These enzymes make a cut DNA at different locations of double helix, called a staggered cut. They will check the DNA in sequence and when their specific point comes, generally it is a palindrome of nitrogen bases, they cut it in away from between, leaving sticky ends.
EcoR1 is restricted to endonuclease isolated from Escherichia coliRY13. The first letter of the name is taken from the genus to which the bacteria belongs to, the next two letters indicate species. R is named after the strain from which it is isolated, the number depends on the order of isolation of enzymes from that particular strain.

Note:
Isolation of two enzymes which were found to be inhibiting the growth of the bacteriophage in E. coli was done in the year 1963. One enzyme was found to be adding methyl groups to DNA and the other one was involved in cutting the DNA helix which was named as the restriction endonuclease.