01. Risk. 

Risk is the possibility you'll lose money if an investment you make provides a disappointing return. All investments carry a certain level of risk, since investment return is not guaranteed.

According to modern investment theory, the greater the risk you take in making an investment, the greater your return has the potential to be if the investment succeeds. For example, investing in a startup company carries substantial risk, since there is no guarantee that it will be profitable. But if it is, you're in a position to realize a greater gain than if you had invested a similar amount in an already established company. As a rule of thumb, if you are unwilling to take at least some investment risk, you are likely to limit your investment return.

Risk

The uncertainty associated with any investment. That is, risk is the possibility that the actual return on an investment will be different from itsexpected return. A vitally important concept in finance is the idea that an investment that carries a higher risk has the potential of a higher return. For example, a zero-risk investment, such as a U.S. Treasury security, has a low rate of return, while a stock in a start-up has the potential to make an investor very wealthy, but also the potential to lose one's entire investment. Certain types of risk are easier to quantify than others. To the extent that risk is quantifiable, it is generally calculated as the standard deviation on an investment's average return.

02. Systemic Risk

A risk that is carried by an entire class of assets and/or liabilities. Systemic risk may apply to a certain country or industry, or to the entire globaleconomy. It is impossible to reduce systemic risk for the global economy (complete global shutdown is always theoretically possible), but one may mitigate other forms of systemic risk by buying different kinds of securities and/or by buying in different industries. For example, oil companies have the systemic risk that they will drill up all the oil in the world; an investor may mitigate this risk by investing in both oil companies and companies having nothing to do with oil. Systemic risk is also called systematic risk or undiversifiable risk. Systemic Risk also called undiversifiable risk or market risk which is risk that's characteristic of an entire market, a specific asset class, or a portfolio invested in that asset class. It's the opposite of the risk posed by individual securities in a class or portfolio, also known as nonsystematic risk. The predictable impact that rising interest rates have on the prices of previously issued bonds is one example of systematic risk. A good example of a systematic risk is market risk. The degree to which the stock moves with the overall market is called the systematic risk and denoted as beta.

http://financial-dictionary.thefreedictionary.com/Systematic+Risk

03. Unsystematic risk

What Does Unsystematic Risk Mean?

Company- or industry-specific risk as opposed to overall market risk; unsystematic risk can be reduced through diversification. As the saying goes, “Don't put all of your eggs in one basket.”

Also known as specific risk, diversifiable risk, residual risk and idiosyncratic risk. Unsystematic risk or risk that is uncorrelated to the overall market risk. In other words, risk that is firm-specific and can be diversified through holding a portfolio of stocks.

Also called the diversifiable risk or residual risk. The risk that is unique to a company such as a strike, the outcome of unfavorable litigation, or a natural catastrophe that can be eliminated through diversification. Risk that is unique to a certain asset or company. An example of nonsystematic risk is the possibility of poor earnings or a strike amongst a company's employees. One may mitigate nonsystematic risk by buying different of securities in the same industry and/or by buying in different industries. For example, a particular oil company has the diversifiable risk that it may drill little or no oil in a given year. An investor may mitigate this risk by investing in several different oil companies as well as in companies having nothing to do with oil. Nonsystematic risk is also called diversifiable risk.