Someone told me Buddha copied almost everything from Brahmanism, how accurate is that? I am fairly new to the Dhamma and this site specifically. I was told by an Indian person that dyana (meditation) was a part of a yoga system which became zen in china, dharma became dhamma, most of Buddhists texts are sutras, ideas of reincarnation, maya (phenomenon), nirvana, samaddhi, sat (truth), chitta (conciousness), daya (compassion), ahinsa are all Hindu themes reinterpreted.

How much did Sakyamuni reinterpreted on Brahmanism and how much is disinformed?
Dyana meditation is basically keeping your focus on one object. Various forms of it can be found in many religions. There's nothing exceptional about it. Even christians/muslims praying to a God is a type of concentration meditation that could lead to the first Dyana. In that case, the object of focus is conceptual or fictional.

In Buddhism also you can find types of Dyana meditations as they are useful methods of developing concentration and subduing defilements. But what makes Buddhism exceptional is Vipassana meditation. This meditation is not found in any other religion. Then there are so many unique teachings like the four noble truths, the noble eightfold path, most of the teachings in the sutta, abhidhamma, vinaya pitakas that amount to 84,000 teachings. 

So if someone claims that the Buddha copied almost everything from Yoga, it only speaks of his lack of knowledge in Buddhism.