Resistance and Support what does it mean, related to cryptocurrency values?
Rates
We all know the value of cryptocurrencies changes, a lot. That is the fun, for day-traders a quick change of value from high to low or the other way around can make a difference between loss and win. For longterm traders these quick changes have no value.
Still both of them will look at the rate's history and try to determine whether it is going to increase or decrease.
Resistance
When people say, there is a resistance at $9,000, it means the cryptocurrency has a hard time increasing it's value above $9,000. The chart of the cryptocurrency's value will show a pattern where the value gets quite close to the $9,000 line but doesn't crosses it. Or when it does cross the line, it is not able to stay above it for a long time.
Support
This is sort of the same as resistance but on the lower level side of things. When people say there is support at $9,000, it means the cyptocurrency's value drops multiple times over a period of time but not below $9,000. Or when it does go below $9,000 it doesn't stay there for a long time.
An example chart (DOGE)
The above image is not the best example as the timespan is too short, but it does show the pattern pretty clearly.
You can see it moves up to the $0.0075 line but it is not able to reach it. So there is resistance at $0.0075. At the same time you can see it drops to around $0.007 but doesn't go much lower than that for long. So there is support at $0.007.
Changing roles
Once a rate breaks through the resistance, this happens when it is able to stay above a certain value, it will most of the time increase some more quickly and drop after that. With this drop the former resistance value will become the new support value.
This also applies to the support value. When a rate goes below the support value, it will most likely lower in value some more and the former support value will become the new resistance value.
In short
When values break through resistance or support, great value changes are possible.