In high school debate, it was referred to as "grounds"- essentially, laying out definitions for terms important or relevant to the topic established the terrain

In high school debate, it was referred to as "grounds"- essentially, laying out definitions for terms important or relevant to the topic established the terrain, to use a battle metaphor. If you're using the same words but with different beings, it's like two opposing forces not being on the same field of battle. Two ships passing in the night is another metaphor, and is probably more common in English as a phrase.