branch line | cut line | slit

A branch cut is a curve (with ends possibly open, closed, or half-open) in the complex plane across which an analytic multivalued function is discontinuous. For convenience, branch cuts are often taken as lines or line segments. Branch cuts (even those consisting of curves) are also known as cut lines, slits, or branch lines.

branch | branch point | cut | discontinuity | inverse hyperbolic functions | inverse trigonometric functions | multivalued function | principal branch | principal value | Riemann surface