These are some definition of earmarking.

http://www.thefreedictionary.com/Earmarking

 ear·mark

n.

1. An identifying feature or characteristic: a novel with all the earmarks of success.

2. An identifying mark on the ear of a domestic animal.

tr.v. ear·marked, ear·mark·ing, ear·marks

1. To reserve or set aside for a particular purpose. See Synonyms at allocate.

2. To mark in an identifying or distinctive way.

3. To mark the ear of (a domestic animal) for identification.

 

En.wikipedia.org

Earmarks in public finance

In public finance, an earmark is a requirement that all or a portion of a certain source of revenue (such as a tax) must be devoted towards spending on a specific public expenditure. Earmarking bypasses the normal procedure where tax revenue is pooled in a general fund which is then distributed among separate spending programs.

For example, in the United Kingdom a tax on television licences is directly allocated to the British Broadcasting Corporation (BBC).

Governments are often fond of earmarking, while public finance experts often criticize earmarking since it provides an avenue for corruption including kickbacks and because it reduces the discretion and flexibility of the government, which may lead to a loss in economic efficiency.

“often reflecting procedures established over time that may differ from one appropriation bill to another. For some bills, an earmark may refer to funds set aside within an account for a specified program, project, activity, institution, or location. In others, the application may reflect a more narrow set of directives to fund individual projects, locations, or institutions.”

 “uses a different definition of earmarks, namely specified funds for projects, activities, or institutions not requested by the executive, or add-ons to requested funds which Congress directs for specific activities.”

 Not specifically authorized; Not competitively awarded; Not requested by the President; Greatly exceeds the President’s budget request or the previous year’s funding; Not the subject of congressional hearings; or Serves only a local or special interest.” ^[2]