rely on/upon somebody/something phrasal verb (see also rely)

1. to trust or depend on someone or something to do what you need or expect them to do ⇒ reliable, reliance:
I knew I could rely on David.
rely on somebody/something to do something
Many working women rely on relatives to help take care of their children.
rely on/upon somebody/something for
Many people now rely on the Internet for news.

2. to depend on something in order to continue to live or exist:
For its income, the company relies heavily on only a few contracts.
rely on/upon somebody/something for
They have to rely on the river for their water.

[TahlilGaran] Dictionary of Contemporary English ▲