Greek Zero Sign (U+1018A) is a Unicode other number from the Ancient Greek Numbers block. It resides on Plane 1 (SMP, Supplementary Multilingual Plane), has bidirectional class ON (other neutrals), is not mirrored, and has combining class 0 (Not Reordered). In HTML it can be written as 𐆊 or 𐆊. Because it is outside the Basic Multilingual Plane, proper font support is required; otherwise a fallback box may be shown.