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: friction causes the temperature of an object to increase. 
Sentence2: pressure causes the temperature of an object to increase.
Example Output: causes

Example Input: Sentence1: Scyphozoans are the next group of Cnidarians, and they are the familiar jellyfish. 
Sentence2: Scyphozoans are aquatic organisms.
Example Output: Scyphozoans

Example Input: Sentence1: DNA replication is the process in which DNA is copied. 
Sentence2: DNA is copied in connection with celldivision.
Example Output:
copied