A super-Earth refers to an extrasolar rocky planet that has more mass than planet Earth. However, when compared with other Solar System's ice giants such as Neptune and Uranus, the size of a super-Earth is smaller than these two. The term super-Earth is used majorly to compare the size of this newly found planet and the existing one (Earth).
That said, scientists do not usually compare super-Earths and the real planet Earth in terms of conditions such as temperature, orbital properties, compositions, and habitability. This means the term super-Earth is only referring to rocky planets with no atmosphere. The first-ever super-Earths were discovered in 1992 by Dale Frail and Aleksander Wolszczan.
These super-Earths were found to be four times larger than Earth, but they were too small when you compare their masses with some of the Solar System's gas giants. Apart from the first two that were discovered in 1992, more super-Earths have been discovered.