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.

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

Sentence1: Acids dissolve in base and turn blue litmus red. 
Sentence2: acid changes color.
Acids

Sentence1: Dinosaurs are the most celebrated fossil organisms. 
Sentence2: Dinosaurs are the most celebrated fossil fuel.

Dinosaurs