Английский словарь американских идиом - fall back on

or fall back upon v. 1. To retreat to. * /The enemy made a strong attack, and the soldiers fell back on the fort./ 2. To go for help to; turn to in time of need. * /When the big bills for Mother's hospital care came, Joe was glad he had money in the bank to fall back on./ * /If Mr. Jones can't find a job as a teacher, he can fall back on his skill as a printer./