Sentence:  From its inception in 1920 with the passage of Public Law 236 , 66 th Congress , the purpose of the vocational rehabilitation program has been to assist the States , by <WSD>means</WSD> of grants-in-aid , to return disabled men and women to productive , gainful employment . 
Meaning of the word marked with <WSD> tags:  how a result is obtained or an end is achieved