1 /di'vaId/ verb
a) (T) to separate something such as an area, group, or object into two or more parts: divide sth into: Take the orange and divide it into quarters. | The USA is divided into 50 states. | divide sth between: Hitler and Stalin divided Poland between them.
b) (I) to become separated into two or more different parts
(+ in/into): The cell quickly divides in two.
2 KEEP SEPARATE also divide off (T) to keep two areas separate from each other: The Berlin Wall used to divide East and West Berlin. | divide sth from: The chapel is divided from the rest of the church by a screen.
3 SHARE also divide up (T) to separate something into two or more parts and share them between two or more people: divide sth between/among: The money is to be divided up equally among the six grandchildren.
a) (T) to find out how many times one number is contained in another larger number: divide sth by sth: Divide 21 by 3. | divided by sth: 6 divided by 3 is 2.
b) (I) to be contained in another, usually larger, number one or more times
(+ into): 8 divides into 64. —compare multiply (2)
5 DISAGREE (T) to make people disagree with each other and form groups with opposing views: be divided over/about (=disagree about something): Voters are bitterly divided over the issue of gun control.
6 dividing line the difference between two types or groups of similar things
(+ between): There's a thin dividing line between genius and madness.
7 divide and rule to control people by making them argue or fight with each other instead of opposing you
— divided adjective 2 noun (countable usually singular)
1 a difference between two groups of people, especially in their beliefs or way of life, that makes them seem separate from each other: two politicians on either side of a political divide
2 AmE a line of high ground between two river systems; watershed (3)

Longman dictionary of contemporary English. 2004.