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: Lymph is a fluid that leaks out of capillaries into spaces between cells. 
Sentence2: Humans are made up of trillions of cells.
Example Output: cells

Example Input: Sentence1: when a river floods , that river deposits soil in flood plains. 
Sentence2: Hurricanes can cause local flooding, flash flooding, or coastal flooding.
Example Output: flood

Example Input: Sentence1: Severe weather patterns and high winds can also cause localized damage. 
Sentence2: movement of an air mass can cause localized damage.
Example Output:
damage