Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Example Input: Sentence1: June Summer Triangle Three bright stars light up the summer sky. 
Sentence2: Nuclear reactions in stars cause them to brighten up the summer sky.
Example Output: bright

Example Input: Sentence1: the mass of an object causes the gravitational force exerted by that object. 
Sentence2: gravitational force accelerates objects.
Example Output: force

Example Input: Sentence1: a airplane is used for moving people across bodies of water. 
Sentence2: Oceans are large bodies of salt water which separates deposits of land.
Example Output:
bodies