Sentence:  Note that the mass scale <WSD>is</WSD> one to two orders of magnitude greater than some previously used ; for example , Jacchia ( 1948 ) derived a scale of 0.15 g for a * * f , zero magnitude meteorite . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)