The meniscus is the "pulled up" water along the glass walls.
A meniscus is a curve in the surface of a molecular substance (water, of course) when it touches another material. With water, you can think of it as when water sticks to the inside of a glass.
Adhesion is responsible for a meniscus and this has to do in part with water's fairly high surface tension. Water molecules are attracted to the molecules in the wall of the glass beaker. And since water molecules like to stick together, when the molecules touching the glass cling to it, other water molecules cling to the molecules touching the glass, forming the meniscus.
>> The Water Science School page about a meniscus.