'MoWoG' was moulded in to many castings used in MG, Austin and Morris engines over many years. And speculation, not to say argument, is rife amongst MG aficionados as to what it means.
Some say 'MoWoG' is the name of a god that has to be appeased with many offerings of fluids and expensive new parts, otherwise 'he' (or more probably 'she') will cause breakdowns at most inopportune moments.
Others say it was a joke by a foreman in the casting shop many years ago, knowing that it would plague owners for years to come.
The truth is a little more prosaic - it probably represents the merger of MG and Wolseley into Morris Motors and the use of common parts from that point. Most agree that the 'Mo' stands for 'Morris' and the 'Wo' for 'Wolseley'. But that still leaves plenty of room for argument as to what the 'G' stands for.
Clausager, in his essential bible on the MGB - Original MGB - mentions in passing that it stands for 'MG'. A spokesman for The British Motor Museum in the first issue of their magazine answered the specific question by categorically stating that it stood for 'Group'. However he then went on to say 'But why would anyone want to know?' which in my opinion casts immediate doubt on his credentials, and even his right to be part of The British Motor Museum!
For my part, I am now firmly in the 'MG' camp. Not because of a loyal desire for it to be so, but through a study of the evidence. The source of the greater part of this evidence is David Knowles incredibly detailed book - MG The Untold Story. David relates how Wolseley and MG were owned personally by Lord Nuffield until he was convinced to merge it with Morris Motors in 1935. He also states that, once part of Morris Motors and all design was being carried out at Cowley, the chassis and engine number prefixes and suffixes for Wolseley variants were 'W' and for MG were 'G'. It doesn't take much of a leap of faith to assume that 'M' was already being used by Morris (hence the 'G' for MG since there wasn't much choice for anything else). I would also say it would be extremely unlikely for someone to go to the bother of devising a 'logo' to mark the merger of Wolseley and Morris but to ignore MG which was merged at the same time. Finally, there never was a 'Morris Wolseley Group' as an organisation, just 'Morris Motors Ltd'.
I rest my case, M'Lud.