What's an adjective to describe something "Of or relating to a row"?
Ordinal:
of or relating to a thing's position in a series
Source: Google "ordinal definition" I don't know what Google's source for definitions is.
A row is basically a group of something arranged in a line. A row of houses. A row of seats. It rained for five days in a row.
Hence, a good word to describe something relating to a row would be linear.