Themes

I tend to think of it, and explain it as 'the main menu bar' of which the 'custom menu' (in flexibase anyway) is a part - but I wouldn't expect most site users to know what the custom menu is, other than those with access to the theme settings to create it in the custom menu box

If Im talking to users, I also tend to refer to the awesomebar as 'the top black bar', as I wouldn't expect most of them to think its particularly awesome, just that its a useful part of the interface - tends to be those of us who know what its like without it and appreciate the work that went into creating it originally who think it really is an 'awesome bar' But then I tend to limit the awesomebar on my work site to site admins/managers only anyway, and most of them work in the same office as me, which makes explaining 'the top black thing' much easier than when writing proper docs for it (at which point it does get labelled as 'awesomebar' in a diagram and then referred to as such in any docs.)

I think a labelled diagram such as the one you have done, with the names you want to use and then consistently use those throughout your doc is probably the best way to go