The name "Nara-Narayana" can be broken into two Sanskrit terms, Nara and Narayana.
 Nara means Human, and Narayana refers to the name of the deity.

Monier-Williams dictionary says Nara is "the primeval Man or eternal Spirit pervading the universe always associated with Narayana, "son of the primeval man"; both are considered either as gods or sages and accordingly called देवौ, ऋषी, तापसौ.
In epic poetry, they are the sons of Dharma by Murti or Ahimsa and emanations of Vishnu, Arjuna being identified with Nara, and Krishna with Narayana.- Mahabharata, Harivamsa and Purana".
Narayana and Nara both are forms of Vishnu.
The name "Nara-Narayana" can be broken into two Sanskrit terms, Nara and Narayana.  Nara means Human, and Narayana refers to the name of the deity.
Monier-Williams dictionary says Nara is "the primeval Man or eternal Spirit pervading the universe always associated with Narayana, "son of the primeval man"; both are considered either as gods or sages and accordingly called देवौ, ऋषी, तापसौ. In epic poetry, they are the sons of Dharma by Murti or Ahimsa and emanations of Vishnu, Arjuna being identified with Nara, and Krishna with Narayana.- Mahabharata, Harivamsa and Purana". Narayana and Nara both are forms of Vishnu.
Nara-Narayana