In its larger meaning "Imperial / Made for the emperor" also a specific Imperial Celadon ware probably first made in Kaifeng during the Northern Song and then continued in Hangzhou during the Southern Song.
Guan makes together with Ge, Ding, Jun and Ru up the 'Five Great Song Wares'. While each of these wares has its own distinctive characteristics the southern crackled wares of Guan and Ge have retained their mystery. While no unaminity of opinion have been reached it is generally thought that those wares with a single network of wide dark grey crackles are Guan, and those with a double crackle jinsi tiexian (gold thread and iron wire), should be designated Ge.
Guan ware, literally means "official" ware; so certain Ru, Jun, and even Ding could be considered 'Guan' in the broad sense of being produced for the court. In its narrow meaning the term only applies to what was produced by an official, imperially-run kiln, which did not start until the Southern Song fled the advancing Jin and settled at Lin'an.