Samadhi is Sanskrit and is usually translated as concentration but it is a high degree of concentration, one-pointedness, that is often experienced as spiritual bliss. Every meditator eventually experiences it except those who meditate while ignoring the precepts and the third, fourth and fifth folds of the eightfold path. It is often called kensho in Japanese.
Having a samadhi experience does not mean that one has attained enlightenment.
There are many different levels of samadhi. The experience may be brief in time or lengthy. It may be deep or shallow. That’s why we have teachers. They can let us know if we have had a deep experience or just a makyo, an experience of delusion.