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: After a seed is planted it is watered. 
Sentence2: seeds need water.
Example Output: seed

Example Input: Sentence1: Average vehicle speed rises by only 0.3 miles per hour. 
Sentence2: a speedometer measures miles per hour.
Example Output: hour

Example Input: Sentence1: evaporation can be used for separating a solute from a solvent in a solution. 
Sentence2: evaporation can be used to move a solute apart from a solvent in a solution.
Example Output:
evaporation