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: electric devices require electrical energy to function. 
Sentence2: Lie detectors are electrical or mechanical devices.
devices

Sentence1: Boiling water can cause burns. 
Sentence2: heating water can cause burns.
water

Sentence1: an animal requires warmth for survival. 
Sentence2: Heat is produced to maintain warmth in the boy.

warmth