Name #963 of 1000 · Viṣṇu Sahasranāma
तत्त्वम्tattvam
Tattvam
The Reality — the "thatness" of all things
From shloka 103 · chapter Kalki
प्रमाणं प्राणनिलयः प्राणभृत्प्राणजीवनः ।
तत्त्वं तत्त्वविदेकात्मा जन्ममृत्युजरातिगः ॥
pramāṇaṃ prāṇanilayaḥ prāṇabhṛtprāṇajīvanaḥ
tattvaṃ tattvavidekātmā janmamṛtyujarātigaḥ
Also in this shloka: pramāṇam · prāṇanilayaḥ · prāṇabhṛt · prāṇajīvanaḥ · tattvavit · ekātmā · janmamṛtyujarātigaḥ