Taxable expenditure, income, or investment on which no tax is levied to serve a specific purpose (such as to encourage a certain activity) for a

The general term for efforts by individuals, corporations, trusts and other entities to evade taxes by illegal means. (source: http://en.wikipedia.org/wiki/Tax_evasion)

Deduction, exclusion, or exemption from a tax liability, offered as an enticement to engage in a specified activity (such as investment in capital goods) for

Tax liability is the payment owed by an individual, business, or other entity to a federal, state, or local tax authority. (source: investopedia.com )

A tax office is a governmental office engaged in collection of revenue through taxes. (source: http://standards.phorio.com/?t=definition&code=3817677034)

Amount of income, property, or sales tax levied on an individual or business. (source: http://www.investorwords.com/8711/tax_burden.html#ixzz25gw1Vgya)

A declaration to the tax authorities of how much you have earned during a particular year, used to calculate how much tax you will have

A reduction of the income subject to tax for expenses incurred in trading or carrying on the trade or business. (source: http://en.wikipedia.org/wiki/Tax_deduction)

A reduction of the income subject to tax, for various items, especially expenses incurred to produce income. (source: http://en.wikipedia.org/wiki/Tax_deduction)