18.

U+2499, ⒙
NUMBER EIGHTEEN FULL STOP

[U+2498]
Enclosed Alphanumerics
[U+249A]

Icelandic

Icelandic numbers (edit)
 ←  17 18 19  → 
    Cardinal: átján
    Ordinal: átjándi
    Ordinal abbreviation: 18.
    Fractional: átjándi

Adjective

18. (indeclinable)

  1. 18th