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: freezing means changing from a liquid into a solid by reducing heat energy. 
Sentence2: Water freezes into ice when cooled.
Example Output: freezing

Example Input: Sentence1: Sweat glands produce more sweat. 
Sentence2: When the body is hot, something coming from a gland is produced to cool the body.
Example Output: glands

Example Input: Sentence1: Plants detect and respond to the daily cycle of light and darkness. 
Sentence2: bamboo detects and responds to the daily cycle of light and darkness.
Example Output:
cycle