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: Pre-osteoclasts float freely in bones' marrow canals and mature into osteoclasts. 
Sentence2: The cells that eventually develop the ability to heal fractures are found free floating in bone marrow.

freely