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: Basically, heat is energy. 
Sentence2: Head hair is especially important in preventing energy loss from the body.
Example Output: energy

Example Input: Sentence1: Butter is a fat that is a solid at room temperature. 
Sentence2: Butter is a fat that is a solid between 5 and 27 degrees Celsius.
Example Output:
Butter