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: the ovaries are used in reproduction. 
Sentence2: Unlike most female animals, which have two functioning ovaries, the chicken usually has only one.
Example Output: ovaries

Example Input: Sentence1: Propane can be either a liquid or a gas. 
Sentence2: heat can be added to propane to change it's properties through the boiling process.
Example Output: Propane

Example Input: Sentence1: dehydrating food is used for preserving food. 
Sentence2: Our Nesco Food Dehydrators require no tray rotation due to a patented air flow system.
Example Output:
dehydrating