Addition
Part of speech: noun
Definition: The act of adding anything. Anything that is added. The process of adding.
Example sentence: One of the things I've always liked about my husband is he's very good at lots of stuff. He was an English teacher when I met him. He wrote poetry and played the guitar. As time went on, he decided to go into economics, so he's very analytical and mathematical in addition to his artsy side.
Improver
Part of speech: noun
Definition: Something that, or someone who, improvesA substance added to cause improvement (especially to a foodstuff)