The visible series in the hydrogen spectrum is called the Balmer series.

Here's why:

* Spectral Series: When electrons in a hydrogen atom transition between energy levels, they emit or absorb light. These transitions result in distinct wavelengths, which we see as spectral lines. A series refers to a group of spectral lines that share a common lower energy level.

* Balmer Series: The Balmer series is defined by electron transitions that end in the second energy level (n=2). The visible light we see from hydrogen comes from these specific transitions.

Let me know if you'd like more details on the Balmer series or other spectral series in hydrogen!