“Passive income is an income that a person gets regularly.”
It does not have to be regular. Stocks can skip dividend payments.

“Any other income a person makes by doing little or nothing.”
“Doing little,” other than investing capital, which can be a full time, job to be successful.

“Article writing,”
Article writing is work, by any definition of the word, writing is not passive.

“Passive income is a taxable income,”
Maybe it is, maybe it is not. You can own tax-free bonds for example.

“Passive income does not include the earnings from your wages, dividends, capital gains or interest.”
Passive income "may include," the dividends, capital gains, and interest.

If you believe the market is efficient, and it is impossible to outperform the market, then passive investing, or indexing is probably the way to go. Historically passive funds have out performed the majority of active funds

Dean LeBaron's Treasury of Investment Wisdom: 30 Great Investing Minds by Dean LeBaron and Romesh Vaitilingam ISBN-10: 0471152943 pg47

See:

You are confusing capital gains with nominal gains and are once again confusing the wording that is used by investors. This is due to your dictionary definitions of the words.

Capital gains is the profit on the sale of something you hold. As in the childish remark of a kid selling a bicycle we all know that anyone who earns less then $600 p/year does not have to pay taxes. Sorry I was dealing in the adult World. The Capital gains tax is on people who hold long-term assets. You can have gains on the sale of asstes but in the tax world capital gains is on the sale of long-term assets. I am only dealing with USlaw as it is the Country I work out of. I did not realize owl was such a global person dealing in the tax laws of many Countries. Butr from a US tax perspective you can have a gain on the sale of property and a capital gain is on the sale of a long term asset being sold. Even a child who sells a bicycle has created a taxable event on the gain in the sale of their bicycle if they make more than $600 p/year. From a tax perspective if they only owned the bicycle for a short period of time they do not have a capital gains tax but just ordinary tax on the sale. Wording is everything and especially in taxes.

No you are looking at this from a macro standpoint when you need to look at it from a microeconomic standpoint. If you have capital gains there is then a taxable event. You may have losses to offset the capital gains but the capital gains within itself is a taxable event. Therefore your view of the situation of the owner is incorrect. As the offset here might have been used to offset another taxable event and therefore results in a net tax payment.

Capital gain
A capital gain is a profit that results from investments into a capital asset, such as stocks, bonds or real estate, which exceeds the purchase price. It is the difference between a higher selling price and a lower purchase price, resulting in a financial gain for the investor.

Conversely, a capital loss arises if the proceeds from the sale of a capital asset are less than the purchase price.

What bklynjs is addressing is that he thinks that in all lands through out all time, even before the United States was a colony, that capital gains constitutes income. And he believes that all income is taxable to everyone throughout all time, and in all places, that gains on capital have occurred.

The ideal investment has four elements.
Safety of principle
Income
Liquidity
and Capital gain

Capital gain refers to the fact that your capital increases in a particular currency. It may have not gained at all in real terms. Capital gain, has nothing at all to do with the holding period, because in the USA anyway. Organized regulated futures exchange traders, can have capital gains on instantaneous transactions.

You do not have to hold it any particular time period for it to be considered a capital gain. You just need to sell something for more than you paid for it. That is, your your capital has to grow. Thus it is called Capital gain.

Not all countries impose a tax on capital gains of individuals and corporations. So, Capital gain has nothing to do with whether or not you pay taxes on it. This is also true of earning capital gains using tax-free instruments.

“In an inflationary environment, capital gains may be, to some extent, illusory. If prices in general have doubled over five years, then selling an asset for twice the price it was purchased at five years earlier represents no real gain at all.”

If a child buys a bicycle and later sells it for a higher price. He may experience a capital gain. She sells it for more than she paid. The holding period long term, or short term, does not apply. If the kid earned less than a certain amount that year she is not subject to any tax reporting, or paying of tax whatsoever. But she still has a capital gain. So, like the dictionary says: Capital gain is a profit from the sale of property, or of an investment.

The Dictionary says:

Capital gain |ˌkæpədl ˈgeɪn|
noun (often capital gains)
a profit from the sale of property or of an investment.

Wikipedia says:

http://en.wikipedia.org/wiki/Capital_gain

A capital gain is a profit that results from investments into a capital asset, such as stocks, bonds or real estate, which exceeds the purchase price. It is the difference between a higher selling price and a lower purchase price, resulting in a financial gain for the investor. Conversely, a capital loss arises if the proceeds from the sale of a capital asset are less than the purchase price.