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: Dams are very damaging to rivers. 
Sentence2: Creating a lake can be very damaging to rivers.
Example Output: damaging

Example Input: Sentence1: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.
Example Output: Earthquakes

Example Input: Sentence1: Seed refers to offspring, children. 
Sentence2: Organisms give rise to children by reproduction.
Example Output:
children