The Shield is based upon the Arms or Three Chevronels Gules which belonged to the Clare Family, who held the medieval lordship of Glamorgan.
The wavy chief is taken from the Arms of the former Cynon Valley Borough Council, and refers to local rivers. The acorns come from the former Borough of Rhondda, where they represented the ancient forest and the growth of new industries. The celestial crown is taken from the Arms of the former Borough Council of Taff Ely, and its predecessor Llantrisant and Llantwit Fardre Rural District Council.
The Crest is the Welsh symbol of a dragon, here depicted as a demi dragon in allusion to the Crests of the constituent bodies making up the new authority. It emerges from flames in token of the regeneration of industry, and holds a flash of lightning as an emblem of new technology.
The dexter Supporter to the Shield is a laboratory technician, representing the new forms of industry attracted to the area. The sinister Supporter of a miner is taken from a Supporter to the Arms of the Former Mid Glamorgan County Council, and stands for the traditional skills of South Wales.
The design refers to the constituent parts of the new authority, and harks back to the old industries while looking forward to emerging technology. The Latin motto, "Adsumus Ut Adiuvemus", translates as "We are here to help".