Risk in economic terms indicates the probability of the occurance of a specific event, which would lead to damage or loss (p.e. the likelihood of losing ship and freight to a hurricane). In distinction to risk, chance indicates the possibility of a positive outcome.
Investments include both risk and chance. This is the so called Risk-Return Tradeoff: low levels of uncertainty offer low potential returns but also low potential losses, whereas high levels of uncertainty offer high potential returns but also high potential losses. Another way many investors quantify and calculate risk is in terms of the standard deviation of returns. This is because all else being equal, risk averse investors prefer returns that are less volatile and more predictable.
Companies try to identify, analyse and control risk through concepts of risk management.
Bonds carry credit risk ("will I get my money back?"), prepayment risk, liquidity risk and interest-rate risk.