The horizontal rows of the periodic table are called periods.
As you can see in the image, the periodic table has 7 periods. As a side note, the vertical rows are called groups - there are 18 of those in the periodic
The periodic table consists of seven rows called periods, and 18 columns called groups or families. The properties of the elements within a period vary across the periodic table in predictable ways, while the elements within a group have similar properties.