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: Humans have collected and grown mushrooms for food for thousands of years. 
Sentence2: Yeast and mushrooms are types of fungus.
Example Output: mushrooms

Example Input: Sentence1: infection can cause bodily tissues to swell. 
Sentence2: Bacteria can cause bodily tissues to swell.
Example Output: bodily

Example Input: Sentence1: a sandbar is formed by water moving sediment downstream. 
Sentence2: Native species, such as cranes, use open water and barren sandbars for roosting at night.
Example Output:
sandbar