The concave mirrors are called "converging mirrors" because they tend to collect light that falls on them, refocusing parallel incoming rays toward a focus.
The concave mirror reflects the parallel rays of light in such a way that after reflection, all the rays converge at one point called focus in front of the mirror. Since a concave mirror converges the beam of parallel light rays. Therefore it is also known as a converging mirror.

Image showing concave mirror as converging mirror

Some of the learners also asked:
What kind of image will be obtained by the converging mirror when the object is placed close to concave mirror?