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: Every photograph is produced by a camera. 
Sentence2: Photographers record images.
Example Output: photograph

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: Pysical weathering is the mechanical breakdown of rocks. 
Sentence2: Physical weathering is when rocks are broken down by means.
Example Output:
Pysical