Lang syne and Old times

Lang syne adverb - Of the distant or comparatively distant past.

Old times and lang syne are semantically related. In some cases you can use "Old times" instead a noun phrase "Lang syne".

Old times noun - Past times remembered with nostalgia.

Lang syne and old times are semantically related. Sometimes you can replace phrase "Lang syne" with "Old times", this phrases are similar.