Acre Syllabification: (A·cre)Definition of Acre 1 /ˈäkər, ˈākər/ an industrial seaport of Israel; population 46,300 (est. 2008). Also called Akko. 2 /ˈäkrə, ˈäkrā/ a state in western Brazil, on the border with Peru; capital, Rio Branco. Acre in other Oxford dictionaries Definition of Acre in the British & World English dictionary