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: healing requires rest. 
Sentence2: healing requires time.
Example Output: healing

Example Input: Sentence1: Digestion is the process of breaking down food into components the body can absorb. 
Sentence2: Saliva starts to break down the food.
Example Output: breaking

Example Input: Sentence1: if something is outside during the day then that something will receive sunlight. 
Sentence2: if something is outside during the day then it will receive UVA and UVB rays.
Example Output:
day