老（old), original meaning is old, 老人（old people).
But 老 can be other meanings, e.g.
1, "always" 他老是这样（He always acts like this)
2, "over cooked", 这个肉煮得太老（This meat is over cooked)
3, for respect when following an old specialist's surname. e.g. 刘老
4, generous appellation for middle age or seniors colleagues or friends，it's added before a surname . e.g. 老张，老王，老李
5, for ages. e.g. 老朋友（old friends), 这座房子很老了(this building is very old)