When one eyebrow is drawn but the other eyebrow is not hidden by hair but is missing entirely. This may either mean the eyebrows would be unobscured but clearly only one eyebrow exists, or one eyebrow is covered and visible through hair yet the other is nowhere to be seen.

Not for use with the likes of [[cyclops]] since they are single-eyed beings, and not to be confused with [[unibrow]].
single eyebrow