An advice is a hint, suggestion or counsel given to you by someone.
In constitutional law Advice is a frequently binding instruction issued to a constitutional office-holder or institution. For example, Queen Elizabeth II of the United Kingdom formally appoints Ministers of the Crown on the advice of the British Prime Minister.
In some cases, whether the advice is mandatory or advisory depends on the context and authority of the person offering advice. Hence in normal circumstances when the President of Ireland is advised to dissolve Dáil Éireann (the House of Representatives), by the Taoiseach (prime minister) he or she must do so. However, where in the words of the Irish Constitution a taoiseach has "ceased to retain the support of a majority in Dáil Éireann"1 (ie, lost the House's confidence) the President had the option of refusing to follow that advice.
To indicate that what is being received is not merely an informal suggestion but a formal constitutional instruction which potentially may be obligatory to follow, some though not all constitutional writers capitalise the word, writing it as Advice.
In aspect-oriented programming an advice is a piece of code executed when a join point is reached, that is associated with the pointcut of the advice.
