Real Dictionary

dismiss
verb: If you are dismissed by someone in authority, they tell you that you can go away from them.
verb: If you dismiss something from your mind, you stop thinking about it.
verb: If you dismiss something, you decide or say that it is not important enough for you to think about or consider.
verb: When a judge dismisses a case against someone, he or she formally states that there is no need for a trial, usually because there is not enough evidence for the case to continue.
verb: When an employer dismisses an employee, the employer tells the employee that they are no longer needed to do the job that they have been doing.

dismiss in American English
to send away; cause or allow to leave
transitive verb: to direct (an assembly of persons) to disperse or go

dismiss in British English
to remove or discharge from employment or service
sentence substitute: an order to end an activity or give permission to disperse