The break-up of a marriage, relationship, or association is the act of it finishing or coming to an end because the people involved decide that it is not working successfully. the acrimonious break-up of the meeting's first session. a marital break-up. = collapse
The break-up of an organization or a country is the act of it separating or dividing into several parts. the break-up of British Rail for privatisation At no time did a majority of Czechoslavakia's citizens support the country's break-up