Time horizon measures an expected holding length of your investments and this term is often mentioned in relation to an investment strategy, meaning that a particular strategy (approach) can prefer a certain holding length. Some strategies, such as “buy and hold”, have a long time horizon, contrary to the day trading strategies which have an extremely short time horizon and, of course, there are many strategies in between.
Volatility of a security or an index means the magnitude of changes in its value (price) over time. In more scientific terms, it can be called ‘dispersion’. High volatility usually indicates higher potential returns because investors can make more money with each deal but, at the same time, it implies higher risks because the direction of future price changes is unknown.