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: An intense bright light produces a glare. 
Sentence2: Nuclear reactions in stars cause stars to produce bright glares.
Example Output: bright

Example Input: Sentence1: Light source is an ultra-bright, unbreakable LED Bulb. 
Sentence2: LEDs convert electricity into light and heat energy.
Example Output: LED

Example Input: Sentence1: Placental mammals are the dominant land mammals. 
Sentence2: The African elephant is a placental mammal.
Example Output:
Placental