The incomparable landscape of the Four Corners region, in the desert Southwest of the United States, is dotted with mesas
and with buttes, their smaller siblings. This photo shows mesas and hoodoos
in the background with a butte on the right. It's easy to see that all three are part of an erosional continuum. This butte owes its sheer sides to the thick layer of homogeneous, resistant rock in its middle. The lower part is sloping rather than sheer, because it consists of mixed sedimentary layers that include weaker rocks.
A rule of thumb might be that a steep-sided, isolated flat-topped hill is a mesa (from the Spanish for table) unless it's too small to resemble a table, in which case it's a butte. A larger tableland may have buttes standing beyond its edges as outliers, left behind after erosion has carved away the intervening rock. These can be called buttes témoins or zeugenbergen, French and German terms meaning "witness hillocks."