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: evaporation can be used for separating a solute from a solvent in a solution. 
Sentence2: Evaporation can be used for segregation a solute from a solvent in a solution.
Example Output: a

Example Input: Sentence1: Thrinaxodon, a small Lystrosaurus Zone cynodont, shows many of the characters of the group. 
Sentence2: Thrinaxodon is from the animal family that eventually evolved into mammals.
Example Output: Thrinaxodon

Example Input: Sentence1: Custom foods and meals can be created. 
Sentence2: astronauts require preserved meals for extended flights.
Example Output:
meals