Bollillos refer to Mexican yeast bread/rolls. It is Mexico's savory, course, crusty oval white bread sometimes described as bobbin-shaped. It is  made with a basic dough that is very similar to a French baguette dough. 

These oblong rolls are used to make the Mexican sandwiches known as Tortas and are also eaten warm and freshly baked from the  oven on their own or with a pat of butter. Next to Tortillas , Bolillos is a staple to Mexico where nearly every villiage has a bakery (panaderia ) which makes Bolillos.

Below is a picture of Bolillos which I took and tasted while I visited a bakeshop in Houston, Texas called Panaderia Bolillo