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: Microbes are also called bacteria or microorganisms. 
Sentence2: Disease-causing bacteria have a negative impact on the body.
Example Output: bacteria

Example Input: Sentence1: Dams are very damaging to rivers. 
Sentence2: Creating a lake can be very damaging to rivers.
Example Output: damaging

Example Input: Sentence1: Viruses are not cells at all, so they are neither prokaryotes nor eukaryotes. 
Sentence2: Influenza viruses are classified as orthomyxoviruses.
Example Output:
Viruses