This might sound like a dumb question.. I don't know but what does parallel mean? As in DE?

it means when they take a nakaraan delena scene and recreate it to make it better. Like in 1x22 Damon kissed Katherine on the porch thinking it was Elena, spilling his feelings and telling her how grateful he was that she was there for him. This time in 3x10, we have Elena telling Damon on the porch how grateful she is that he is in her life and they kiss. That's the parallel and this time with the Damon and Elena.

Damon and Elena have alot of paralled scenes.