Glacial Erratic

The Rockefeller State Park Preserve near Pleasantville, New York, features a fine example of a glacial erratic, a giant rock left behind thousands of years ago by a glacier as it moved. In this case, the word erratic functions as a noun. Both the noun erratic and its adjectival form meaning “haphazard” or “inconsistent” derive from Latin errare, “to wander,” the source also of error and knight errant, the term for “a medieval knight who travels about seeking chivalrous adventures.” This is part of a complete episode.