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: high pressure systems cause clear weather. 
Sentence2: Weather Clear weather usually means good visibility.
Example Output: clear

Example Input: Sentence1: Visible and invisible light is energy in the form of electromagnetic waves. 
Sentence2: Eyes are used for seeing animals by sensing electromagnetic waves.
Example Output: electromagnetic

Example Input: Sentence1: Macroevolution is evolution over geologic time above the level of the species. 
Sentence2: Sometimes, an isolated fossil is held up as evidence of macroevolution.
Example Output:
Macroevolution