Patanjali maharaj wrote in chapter 3 definition of dharana dhayana and samadhi
If you read the words and translate word by word from Sanskrit it will not make any sense. So we have been given a watered down version translated by scholars
Even saints like vivekananda yogananda translated it but gave the meaning which would appease the intellectuals but not a Yogi
The true meaning can only be understood when a Yogi can understand how all 3 can be done simultaneously and then it is known as samyama ( sayama)
There are books in Gujarati describing each in about 200 plus pages – since each one of dharana dhayana samadhi has many sub levels – but it is difficult to get to the core
Bhavin