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: Most pituitary hormones control other endocrine glands. 
Sentence2: Hormones tell the ovaries to produce eggs.
Example Output: hormones

Example Input: Sentence1: when a body of water receives more water than it can hold , a flood occurs. 
Sentence2: Floods are deadly, floods are devastating.
Example Output: flood

Example Input: Sentence1: Bacteria may spread directly from one person to another. 
Sentence2: Bacteria and blue-green bacteria are prokaryotic cells.
Example Output:
Bacteria