What is meant by DDoS attack?

Question

DDoS Protection

That is, there is a limit on the number of F5 presses? Or am I not allowed to make more than n requests per second?

Answer 1

A DDoS attack cannot be triggered by manually pressing F5. An attack requires hundreds, thousands, or even tens of thousands of requests per second. Moreover, the power of DDoS attacks is constantly growing.
Examples:

VideoLAN recently suffered a rather unusual DDoS attack. Although the intensity of requests was not very high - from 400 to 1600 requests per second, the botnet managed to create a very large load on the server, as zombie computers did not just go to one of the pages of the site, but downloaded the VLC player distribution kit weighing 22 megabytes. The peak load on the servers reached 292 gigabits per second.
habrahabr.ru/post/178153

The average power of a DDoS attack in RuNet has increased from 34 Mb/s in the second half of 2012 to 5.5 Gb/s in the first half of 2013, while the average duration of DDoS attacks has more than halved
ria.ru/science/20130911/ 962485712.html

Answer 2

Each resource by this implies its own numbers.