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.

Q: Sentence1: a rainbow is formed by refraction of light by separating light into all different colors. 
Sentence2: Rainbows form when raindrops refract sunlight.

A: refraction
****
Q: Sentence1: high pressure systems cause clear weather. 
Sentence2: Weather Clear weather usually means good visibility.

A: clear
****
Q: Sentence1: Reflexology is based on theories that nerve pathways exist throughout the body. 
Sentence2: Reflexology link the cerebellum with motor neutrons throughout the body.

A:
Reflexology
****