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: Eggs are usually laid in a nest. 
Sentence2: birds have nests.
Example Output: nest

Example Input: Sentence1: a stopwatch is used to measure time. 
Sentence2: Time can be measured with a clock or watch.
Example Output: measure

Example Input: Sentence1: pathogens can cause disease. 
Sentence2: Diseases can move through the air.
Example Output:
disease