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: a flower 's purpose is to produce seeds. 
Sentence2: Every job has meaning and purpose.
Example Output: purpose

Example Input: Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: When water vapor condenses overnight, the temperature has reached the dew point.
Example Output: condenses

Example Input: Sentence1: Platypus females lay their eggs in a burrow. 
Sentence2: Mammals do not usually lay eggs.
Example Output:
eggs