A convention I see a lot for joining tables that I personally like is 'Colour_v_Shape', which I've heard folk refer to colloquially as 'versus tables'.
It makes it very clear at a glance that the table represents a many-to-many relationship, and helps avoid that (albeit rare) confusing situation when you try to concatenate two words that might otherwise form a compound word, for example 'Butter' and 'Milk' may become 'ButterMilk', but what if you also needed to represent an entity called 'Buttermilk'?
Doing it this way, you'd have 'Butter_v_Milk' and 'Buttermilk' - no confusion.
Also, I like to think there's a Foo Fighters reference in the original question.
