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: Consider Input: Sentence1: friction causes the temperature of an object to increase.
Sentence2: internal combustion engines get hot.

Output: temperature

Input: Consider Input: Sentence1: if an object is made of a material then that object has the properties of that material.
Sentence2: items properties are the same as the materials the item is made of.

Output: made

Input: Consider Input: Sentence1: Antibodies are large, Y-shaped proteins that recognize and bind to antigens.
Sentence2: Allergic reactions are caused by substances called antigens.
Output: antigens