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: Balance is the ability to sense and maintain body position. 
Sentence2: Another part of the inner ear is used for balance.
Example Output: Balance

Example Input: Sentence1: Food is easier to chew because it is moistened by saliva from the salivary glands. 
Sentence2: steak is easier to chew because it is moistened by saliva from the salivary glands.
Example Output:
because