Please answer the following question: Given the following passage  "In the language of the Noble Eightfold Path, samyaksamādhi is "right concentration". The primary means of cultivating samādhi is meditation. Upon development of samādhi, one's mind becomes purified of defilement, calm, tranquil, and luminous.",  answer the following question. Note that the answer is present within the text.  Question: __ first appeared in the Maitri Upanisad.
A:
samādhi