The term 'put into service' can be broken down into four crossword solutions: AVAILED (7 letters), USE (3 letters), UTILIZE (7 letters), and USED (4 letters). AVAILED means to make something available, while USE means to employ something for a purpose. UTILIZE is similar to USE, but implies that the thing being employed is being USED to its fullest potential. Finally, USED means to have employed something in the past. All of these words imply that something is being employed or made available for a purpose.