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: decomposition increases the amount of nutrients in the soil. 
Sentence2: decomposition increases the amount of cations.
Example Output: amount

Example Input: Sentence1: poisonous darts are used for defense by sea anemones. 
Sentence2: poisonous darts are used for protection by sea anemones.
Example Output: anemones

Example Input: Sentence1: Nephrons are the structural and functional units of the kidneys. 
Sentence2: fluid in the kidneys collect into ducts.
Example Output:
kidneys