rely
v.to need or trust someone or something to help you. You use this when you cannot do something alone and must depend on another person or tool.
v.to depend on someone or something with full trust or confidence; to be dependent on for support or success. Intransitive — requires a prepositional complement to function.
“I rely on my alarm clock to wake me up.”
“Many small businesses rely on social media to reach new customers without spending a fortune on advertising.”
“Modern infrastructure has become so interconnected that urban populations now rely on stable satellite data for everything from financial transactions to emergency response coordination.”
The verb is intransitive and almost always takes the preposition 'on' or 'upon' before the object.
rely vs depend — Depend describes a logical or physical necessity where one thing is controlled by another, while rely emphasizes a personal sense of trust or confidence in someone's support.
Rely is an intransitive verb and cannot take a direct object; it must be followed by the preposition 'on'.
Usage rely on readers · rely heavily · approach rely
“Keron relies on Dani, whose duties include cleaning and dressing him; she relies on him, as her employer.”
“Social care is relied on by people of all ages.”
From Middle English relien, from Old French relier (“fasten, attach, rally, oblige”), from Latin religo (“fasten, bind fast”), from re- + ligo.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.