Sentence:  He concluded that the anaconda 's maximum length <WSD>is</WSD> 12 or 13 ( perhaps 14 ) meters , which would approximate from 39 to 42 feet ( 14 meters is slightly less that 46 feet ) . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)