tangent arc; partial circumscribed halo
Astronomical term for a halo phenomenon where an arc touches the 22° halo; also called 外接ハロ.
See also: 外接ハロ (がいせつハロ)
Tangent arcs often appear above and below the sun.
What you see at the top of this photo is a tangent arc.
Variant with interpunct; less common but still seen.
From English 'tangent arc'.