Definition: 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.
Input: Sentence1: a delta is formed by deposition of sediment at the mouth of a river by water fanning out. 
Sentence2: Alluvial deposits can form deltas where the river flows into a lake or ocean.

by