Définitions
1.InterjectionUsed as a friendly or respectful salutation to acclaim, greet, or welcome someone: (I wish you) all health or good fortune!
2.InterjectionChiefly followed by to (someone or something): used as a salutation to indicate that someone or something is respected or welcome.
3.NounA salutation of "all hail" (interjection interjection sense 1); hence, a salutation indicating respect or welcome.