Lawyer is a general term for a person who is qualified to advise people about the law, to prepare legal documents for them and/or to represent them in a court of law.
In England and Wales, a lawyer who is qualified to speak in the higher courts of law is called a barrister. In Scotland a barrister is called an advocate.
In AmE attorney is a more formal word used for a lawyer and is used especially in job titles: district attorney.
Counsel is the formal legal word used for a lawyer who is representing someone in court: counsel for the prosecution.
Solicitor is the BrE term for a lawyer who gives legal advice and prepares documents, for example when you are buying a house, and sometimes has the right to speak in a court of law.
In AmE solicitor is only used in the titles of some lawyers who work for the government: Solicitor General
Lawyer比较强调职业(profession),干这行的,受过训练可以提供法律咨询/意见的都叫lawyer
Attorney强调被委任(appointment),被授权可以代表委托人行事的叫attorney
Counselor强调律师工作的咨询/顾问方面(counseling),和lawyer差不多,但是不用来指职业(很多职业都有counselor)
Barrister是出庭律师,在法庭上帮人辩护;
Solicitor主要是向委托人获取信息,准备文件,很少出庭;BRE 要出庭也大多只是在初级法院