According to gibbons, this stands for mean rhythm and indicates
The albums general mood. straight from bo diddley land.

Solid-silver beat machine
Hunkin down
Funkin up on magazine
On rhythmeen in new orleans

Drinkin dixie 45 with hot links
In a silver continental
Wired as hell and doin things
Thats what you get on rhythmeen

Oh yeah, way up
Oh yeah, way out
Uh-huh, get on up
Rhythmeen is down
Rhythmeen thing
Mean mean rhythmeen

Cant get enough of that special sauce
The backbeats the big boss
Here comes another dope fiend
Tradin up for rhythmeen

Oh yeah, weird up
Oh yeah, fear not
Uh-huh, get on up
Rhythmeen is down

Leanin on a silver lincoln
A galaxy 500
In a mustang might tchoupitoulas
Rhythmeen up everything