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: a seismometer is used to measure the strength or magnitude of an earthquake. 
Sentence2: Seismometer Calibration : Instructions on how to calibrate a homemade seismometer.
seismometer

Sentence1: a fire requires oxygen to burn. 
Sentence2: If the oxygen is removed, the fire is smothered.
oxygen

Sentence1: pasteurization reduces the amount of bacteria in milk. 
Sentence2: coliform are reduced with pasteurization.

pasteurization