'Low Intelligence Digger'. An acronym used by the lower ranks in the Australian Army. Usually the infantry to describe a new person or just someone that is retarded.
(Noun; 1960s slang) The quantity of marijuana that will fit in a flat Prince Albert pipe tobacco can (a "lid"). It originally held 1-1/2 oz of moister, denser tobacco, so it would hold about 1 oz of dope. If you are too young to remember, you can google image for ( Prince Albert can ).