Sentence:  The most infamous of all was launched by the explosion of the island of Krakatoa in 1883 ; it raced across the <WSD>Pacific</WSD> at 300 miles an hour , devastated the coasts of Java and Sumatra with waves 100 to 130 feet high , and pounded the shore as far away as San Francisco . 
Meaning of the word marked with <WSD> tags:  the largest ocean in the world