"Cry" versus "weep"

When to use cry and when to use weep? Which one goes more formal? Which one should have preference in general use?

Solution 1:

In short, weep is more about tears, while cry is more about the sound.

Merriam-Webster entries:

Weep: [vi 1] to express passion (as grief) by shedding tears

Cry: [vi 2] to shed tears often noisily

Sob: [vi 1b] to cry or weep with convulsive catching of the breath

Solution 2:

Weep is a little more archaic or poetic, so there's a mild preference for using cry instead. The only time you must use weep rather than cry is if you think the wrong meaning of cry will be understood by mistake.