We decided to take a plunge in the cool mountain lake.
Jane took the cold plunge after the Roman bath at the spa.
A plunge in the pool each morning before breakfast always clears my mind.
WordNet 3.0 Sense Numbers: 1
NOTE: usually implies a quantitative change
The stock market experienced a 30 percent plunge on black Monday.
The aircraft made a plunge when it hit a strong downdraft at 30,000 feet.
The country was devastated by the plunge in its currency in the world markets.
John was baffled by his sudden plunge into depression. (figurative)
WordNet 3.0 Sense Numbers: 2