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 battery converts chemical energy into electrical energy. 
Sentence2: Battery electricity comes conversion.
Example Output: battery

Example Input: Sentence1: Producers make food from inorganic molecules. 
Sentence2: Decomposition is the breakdown of organic molecules into inorganic molecules.
Example Output: inorganic

Example Input: Sentence1: Sight is the ability to sense light, and the eye is the organ that senses light. 
Sentence2: sensing light requires the brain.
Example Output:
light