›to share something between several people or organizations: apportion sth between sb/sthThe costs will be apportioned between the buyer and the seller.apportion sth to sb/sthShe apportioned 25% of her estate to her grandchildren.apportion sth among sb/sthInternational agreements apportioning flights among airlines will soon be a thing of the past.
›INSURANCE, LAWto decide who is responsible for an accident or event, especially when deciding how much of the costs each person, insurance company, etc. should pay: I'm not here to apportion blame, but only to try and resolve the problem.Liability was apportioned 80-20 in his favour.
›ACCOUNTING, TAXto divide costs between different accounts or uses: apportion sth between sb/sthItems such as gas and electricity bills can be apportioned between home and work use.