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.

[Q]: 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.
[A]: seismometer


[Q]: Sentence1: an earthquake causes the ground to shake. 
Sentence2: A number of buildings in Istanbul also were damaged in the earthquake.
[A]: earthquake


[Q]: Sentence1: Cancer is a disease that occurs when the cell cycle is no longer regulated. 
Sentence2: Metastatic cancer is cancer that has spread.
[A]:
Cancer