In typography, “rag” refers to the irregular or uneven vertical margin of a block of type. Usually it’s the right margin that’s ragged (as in the flush left/rag right setting), but either or both margins can be ragged.

When setting type with a ragged margin, pay attention to the shape that the ragged line endings make. A good rag goes in and out from line to line in small increments. A poor rag creates distracting shapes of white space in the margin. Don’t rely on the line breaks generated by your software application; get in the habit of spotting and correcting poor rags by making manual line breaks or by editing your copy. Slight adjustments in point size or column width might work as well.