Also Known As: An, Em, Om, Ang.
Mahjong tiles are considered concealed when they’ve not been exposed to the other players. This does not include tiles in the wall, etc., but rather those in play.
To cover with the hand, to hide, the sun obscured by clouds; dark, gloomy, invisible, secret.
An Kang – Concealed Kong
An K’o – Concealed Pung
An Yi Se – Concealed One Color (One Suit)
An Shou – Concealed Hand
See Also: Exposed.