Look at the definition of "tax"from http://www.dictionary.com/browse/tax?s=t:
[taks]
noun
1. a sum of money demanded by a government for its support or for specific facilities or services, levied upon incomes, property, sales, etc.
2. a burdensome charge, obligation, duty, or demand.
verb (used with object)
3. to demand a tax from (a person, business, etc.).
to demand a tax in consideration of the possession or occurrence of (income, goods, sales, etc.), usually in proportion to the value of money involved.
4. to lay a burden on; make serious demands on:
to tax one's resources.
5. to take to task; censure; reprove; accuse:
to tax one with laziness.
6. Informal. to charge:
What did he tax you for that?
7. Archaic. to estimate or determine the amount or value of.
verb (used without object)
8. to levy taxes.
Notice that the wording in the definition includes or points at the word "demand." Taxation is not voluntary. Taxation is forced. If it were voluntary, it would be donation, not something that could be demanded.
In the USA, Britain, Canada, and Australia, taxation is voluntary. How can this be? since the word tax means something that isn't voluntary, but rather is forced? It means that the people voluntarily allow themselves to be forced into it.
Any time you are interested, go here http://www.youtube.com/user/765736/videos?view=0&live_view=500&flow=grid&sort=da or here https://www.youtube.com/user/765736, and find all the videos that have the word "IRS" in their title, and find out that you aren't even required to pay income taxes.
What this means is, that if you don't use the available way to opt out of income and property taxes, then you are being taxed voluntarily.