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.

Example Input: Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: Condensing is a gas turning into a liquid.
Example Output: condenses

Example Input: Sentence1: a tape measure is used to measure length. 
Sentence2: Length The Base unit for length in the metric system is the meter .
Example Output: length

Example Input: Sentence1: If the medicine is in the form of a pill, swallow the pill whole. 
Sentence2: swallowing pills whole is used for curing people when they are sick.
Example Output:
pill