As @Chris Degnen says - it is kind of the opposite of an iterest rate. Lets see if I can give you some more intuition on this.
Risk-free rate and risk premium
Imagine you are making an investmenet, lending money or whatever. You are doing it so that you get back more money than you lent - otherwise why would you.
The interest rate you want to charge has two components - the time-value of money and the risk. Imagine you had absolute certainty that you would be paid back the same value - you would still want some rate of interest - what would be called the "risk-free" rate.
If the is some risk about the value you well get back - from currency fluctuations, default risk, uncertainty over profits, uncertainty over inflation, etc you will also want a 'risk premium' on top of the 'risk-free rate' to compensate you for the risk you are bearing. The greater the risk the greater the premium.
The actual levels of risk premium and risk-free rate are set by the interaction of investors and investees in the financial markets.
If you were asked for 25% interest to borrow £10 for a year you would have to repay £12.50 in the future. i.e. £10 x (1 + 25%)
The flip side is that the value to me NOW of £10 next year is £10/(1+25%) = £8.0 because I could conceptually invest £8 at 25% and have £10 next year. The PRESENT VALUE of £10 one year from now is only £8 - it is valued at a discount. The rate at which it is reduced is called the "discount rate". The further into the future we go, the greater the extent to which value is discounted.
Effect on capital investment
A higher discount rate is like a higher interest rate. Returns on new investment have to be higher and sooner to make sense. Low discount rates mean longer lower return projects become worthwhile, so companies will take on more debt to fund these projects.
The bank lending rates, driven by central bank lending rates are key drivers of company investment as they can borrow money to fund more projects if they think the return exceed the cost of borrowed capital.
So increasing central bank lending rates means that companies will reduce long term low return projects, and reduce the level of debt they take on.