Sentence:  In the Steiners have busy lives without visiting relatives only context can indicate whether visiting relatives is equivalent in meaning to paying visits to relatives or to <WSD>relatives</WSD> who are visiting them , and in I looked up the number and I looked up the chimney only the meanings of number and chimney make it clear that up is syntactically a second complement in the first sentence and a preposition followed by its object in the second . 
Meaning of the word marked with <WSD> tags:  a person related by blood or marriage