The first meaning of دیگر digar is ‘(the) other’:

آن کتاب دیگر را می‌خواهم
ān ketāb digar rā mi xāham
“I want the/that other book.”

The other meaning of this particle is ‘any more, no more’ when dealing with a negative principal verb:

I won’t go there any more. digar ānjā nami ravam .دیگر آن جا نمی‌روم
Do not talk any more! digar harf nazan! !دیگر حرف نزن
Say no more! (colloquial) dige nagu! !دیگه نگو

In addition, this particle can have other syntactic functions in a sentence. It is the same as the English ‘already’ in the following construction:

!دیگر بس است
digar bas ast!
“Enough already!” (colloquial)
!دیگه بسّه
dige basse!
“Enough already!”(colloquial)

Or sometimes:

!بسّه دیگه
basse dige!
“Enough already!”(colloquial)

It also means “else” as in the following:

دیگر چه؟
digar ce
‘What else?’ (colloquial)
دیگه چی؟
dige ci?
‘What else?’ (colloquial)

It also means ‘another (thing),’ ‘something else’:

چیز دیگری می‌خواهید؟
ciz-e digari mi xāhid?
“Do you want another thing?”, i.e., “Anything else?”
چیز دیگری نمی‌خواهید؟
ciz-e digari nami xāhid?
‘Don’t you want another thing?’
‘Don’t you want anything else?’

Sometimes, with positive verbs, it is used with هم ham as a segment:

چیز دیگری هم می‌خواهید؟
ciz-e digari ham mi xāhid?
“Do you want another thing/something else?”, still, “Anything else?”.

A plural form of digar is دیگران digarān means ‘others = the other people’:

دیگران هم این کار را کرده‌اند
digarān ham in kār rā karde-and
“Others have done this too,” or “The other people have done this too.”