Wikipedia
Tathāgata is a Pali and Sanskrit word; Gautama Buddha uses it when referring to himself in the Pāli Canon. The term is often thought to mean either "one who has thus gone" (tathā-gata) or "one who has thus come" (tathā-āgata). This is interpreted as signifying that the Tathāgata is beyond all coming and going – beyond all transitory phenomena. There are, however, other interpretations and the precise original meaning of the word is not certain.
The Buddha is quoted on numerous occasions in the Pali Canon as referring to himself as the Tathāgata instead of using the pronouns me, I or myself. This may be meant to emphasize by implication that the teaching is uttered by one who has transcended the human condition, one beyond the otherwise endless cycle of rebirth and death, i.e. beyond dukkha.
The term Tathāgata has some meanings, but a Buddhism practitioner of austerities who "comes and goes in the same way" is the most common except pronominal meanings. Although sūtras sometimes remind Buddhist that Tathāgata is arhatship, the rank of Buddhism is already insignificant and is in condition to exist as "being in such a state or condition" or "of such a quality or nature". Originally, it is called Tathāgata.
Usage examples of "tathagata".
If I had truly become Tathagata, perhaps I would have had more effect.
Simon forced himself to sit back, relaxing one muscle group at a time while wondering where Tathagata was going with this, and why.
If Tathagata had decided to investigate the arms purchases Simon had been involved in, over the last few years, he and Yalena might well find themselves on the next tramp freighter heading out of the Ngara system.
By the time Tathagata finished his recitation, Simon was ready to step onto the next interstellar transport headed toward Jefferson and assassinate the leadership of POPPA at any and all risk.
Deputy Minister Tathagata has agreed to spend the next couple of days overseeing additional preparations.
From the concept of a central Tathagata in the mandalas as well as the notion of a Supreme Buddha principle beyond the five manifestations, an Adi Buddha or Primordial Buddha was evolved, usually called Vajradhara or Vajrasattva but Samantabhadra among the rNying-ma-pa.
The abbess of bSam-lding monastery and convent was claimed regularly to incarnate the goddess Vajravarahi and the Panchen Lama of Tashilhunpo was the Tathagata or Dhyani Buddha Amitabha.
Thus yi-dam may be peaceful Tathagatas, bodhisattvas and goddesses as well as fierce and special manifestations like the one just described.
Tathagatas, bodhisattvas, goddesses, special tutelaries, ancient teachers and ascetics, reformers and Dalai Lamas.