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: a camera is used for recording images. 
Sentence2: a camera is used for recording binary.
Example Output: camera

Example Input: Sentence1: Hydrogen bonds cause water to expand when it freezes. 
Sentence2: Water freezes into ice when cooled.
Example Output: freezes

Example Input: Sentence1: transpiration is when water vapor moves from plants into the atmosphere. 
Sentence2: Transpiration is the process of water loss from plants through stomata .
Example Output:
transpiration