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: Heat and temperature are the same. 
Sentence2: a thermometer is used to measure heat.
Example Output: Heat

Example Input: Sentence1: Cows are social animals. 
Sentence2: when a cow moves, chemical energy is converted to mechanical energy.
Example Output: Cows

Example Input: Sentence1: sandpaper is used to smooth wooden objects. 
Sentence2: Traditionally, wooden objects are used in decoupage.
Example Output:
objects