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: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.
Example Output: bacteria

Example Input: Sentence1: Batteries are a better source of DC electricity. 
Sentence2: a flashlight requires batteries to produce light.
Example Output: Batteries

Example Input: Sentence1: Digestion is the process of breaking down food into components the body can absorb. 
Sentence2: Food proteins are changed into energy or heat to be used or absorbed by the body.
Example Output:
absorb