1. We had planned to start building the new shopping center next month, but the company’s profits are down so the project has been put on hold for a while.
2. Lorraine was having second thoughts about marrying Phil before both of them finished college. She told him she thought they should put the wedding on hold for a few years.

Synonyms: on the back burner; on ice. On hold specifically refers to postponing some action, whereas put something on ice means to store or reserve some item for later use. Something that is on the back burner has a lower priority or is less important than something else.