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: poisonous darts are used for defense by sea anemones. 
Sentence2: poisonous darts are used for protection by sea anemones.
Example Output: anemones

Example Input: Sentence1: creating wood-free paper does not require cutting down trees. 
Sentence2: creating printed media requires cutting down trees.
Example Output: creating

Example Input: Sentence1: Translation reads the genetic code in mRNA and makes a protein. 
Sentence2: Translation of mRNA into protein involves the interaction of the mRNA with ribosomes.
Example Output:
protein