simple past tense and past participle of unify
"The nations finally unified under a single leader after years of conflict."
In plain English: To unify means to bring different parts together so they act as one single group.
"The separate groups were finally unified under one leader to form a single nation."
formed or united into a whole
"The separate villages merged to form a unified community that shared resources and traditions."
operating as a unit
"a unified utility system"
"a coordinated program"
united into a whole
"The scattered tribes were finally unified into a single nation under one ruler."