Sentence:  While accounts of the progress of the tsunami came in from various points in the Pacific ( Midway reported it was covered with nine <WSD>feet</WSD> of water ) , the Hawaiian station made its calculations and notified the military services and the police that the first big wave would arrive at Honolulu at 23 : 30 Greenwich time . 
Meaning of the word marked with <WSD> tags:  a linear unit of length equal to 12 inches or a third of a yard