'lang syne' definitions:

Definition of 'lang syne'

From: WordNet
adverb
Of the distant or comparatively distant past; "We met once long ago"; "they long ago forsook their nomadic life"; "left for work long ago"; "he has long since given up mountain climbing"; "This name has long since been forgotten"; "lang syne" is Scottish [syn: long ago, long since, lang syne]

Synonyms of 'lang syne'

From: Moby Thesaurus