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: Combustion-related, motor vehicles, wood burning, open burning, industrial processes. 
Sentence2: Combustion is used to produce heat.
Combustion-related

Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: PALight Flashlights are the ultimate personal LED flashlights.
flashlight

Sentence1: Male dogs use pheromones in urine to mark their territory. 
Sentence2: male dogs use natural aphrodisiacs in urine to mark their territory.

Male