Is pointillism a form of Realist/Natural Art or Post-Impressionist art?

pointillism is a form of post-impressionist art. it is not exactly realist or natural, because a pointillist painting would be comprised of tiny dots (which typically is not found in real life).

your word would be isle.

isle is an island or peninsula especially a small one.

if you add the letter "a" you get aisle, which is a passage between 2 rows of something like chairs, shelves, or something else.