Definition: 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.
Input: Sentence1: Birds have very large chest muscles called pectorals which are used to flap the wings. 
Sentence2: Birds use pectorals to move their wings.

pectorals