Real Dictionary

debate
countable noun: A debate is a formal discussion, for example in a parliament or institution, in which people express different opinions about a particular subject and then vote on it.
variable noun: A debate is a discussion about a subject on which people have different views.

debate in American English
discussion or consideration of opposing reasons; argument about or deliberation on a question
to discuss opposing reasons; argue
to dispute about, esp. in a meeting or legislature
intransitive verb: to engage in argument or discussion, as in a legislative or public assembly
noun: a discussion, as of a public question in an assembly, involving opposing viewpoints
transitive verb: to argue or discuss (a question, issue, or the like), as in a legislative or public assembly

debate in British English
noun: a formal discussion, as in a legislative body, in which opposing arguments are put forward
verb: to discuss (a motion), esp in a formal assembly