1.
to rely on sb/sth and be able to trust them :
He was the sort of person you could depend on.
[+ to inf]
He knew he could depend upon her to deal with the situation.
➡ note at trust
2.
to be sure or expect that sth will happen
SYN count on :
Depend upon it (= you can be sure) we won't give up.
[+ -ing ]
Can we depend on you coming in on Sunday?
( formal )
You can depend on his coming in on Sunday.
[+ to inf] ( ironic )
You can depend on her to be (= she always is) late.