योगवासिष्ठः yogavāsiṣṭhaḥ - book-6, chapter-29, verse-82

यथैकरूपा घनता दृषदोऽस्त्यात्मनस्तथा ।
सत्तामात्रैकसामान्यादितरस्याप्यसंभवात् ॥ ८२ ॥

yathaikarūpā ghanatā dṛṣado'styātmanastathā ,
sattāmātraikasāmānyāditarasyāpyasaṃbhavāt 82

82. yathā ekarūpā ghanatā dṛṣadaḥ asti ātmanaḥ tathā
sattāmātraikasāmānyāt itarasya api asaṃbhavāt

82. yathā dṛṣadaḥ ghanatā ekarūpā asti tathā ātmanaḥ
sattāmātraikasāmānyāt itarasya api asaṃbhavāt

82. Just as the density of a stone is of a single, uniform nature, so too is the Self (ātman). This is because of the commonality of mere existence and the impossibility of anything else existing.

Words meanings summery:

• यथा (yathā) - just as, as, in which way

• एकरूपा (ekarūpā) - of one form, uniform, homogeneous

• घनता (ghanatā) - denseness, compactness, solidity, thickness

• दृषदः (dṛṣadaḥ) - of a stone, from a stone

• अस्ति (asti) - is, exists

• आत्मनः (ātmanaḥ) - of the Self (ātman), of the soul, of oneself

• तथा (tathā) - so, similarly, thus

• सत्तामात्रैकसामान्यात् (sattāmātraikasāmānyāt) - due to the commonality of mere existence

• इतरस्य (itarasya) - of anything other than pure existence (of the other)

• अपि (api) - also, even, too

• असंभवात् (asaṁbhavāt) - due to the impossibility, due to non-existence

Words meanings and morphology

यथा (yathā) - just as, as, in which way

(indeclinable)

एकरूपा (ekarūpā) - of one form, uniform, homogeneous

(adjective)

Nominative, feminine, singular of ekarūpa

ekarūpa - of one kind, uniform, homogeneous

Compound type : Bahuvrihi (eka+rūpa)

• eka – one, single
  pronoun (masculine)
• rūpa – form, shape, nature
  noun (neuter)

Note: Feminine nominative singular, agreeing with 'ghanatā'.

घनता (ghanatā) - denseness, compactness, solidity, thickness

(noun)

Nominative, feminine, singular of ghanatā

ghanatā - denseness, compactness, thickness, solidity

Derived from 'ghana' (dense, solid) with suffix '-tā'

दृषदः (dṛṣadaḥ) - of a stone, from a stone

(noun)

Genitive, feminine, singular of dṛṣad

dṛṣad - stone, rock, grinding stone

Note: Context indicates genitive 'of a stone'.

अस्ति (asti) - is, exists

(verb)

3rd person , singular, active, present (laṭ) of as

Root: as (class 2)

आत्मनः (ātmanaḥ) - of the Self (ātman), of the soul, of oneself

(noun)

Genitive, masculine, singular of ātman

ātman - Self, soul, essence, breath

Root: an (class 2)

तथा (tathā) - so, similarly, thus

(indeclinable)

Note: Correlative to 'yathā'.

सत्तामात्रैकसामान्यात् (sattāmātraikasāmānyāt) - due to the commonality of mere existence

(noun)

Ablative, neuter, singular of sattāmātraikasāmānya

sattāmātraikasāmānya - commonality of mere existence

Compound type : Tatpurusha (sattāmātra+eka+sāmānya)

• sattā – existence, being, reality
  noun (feminine)
  Root: as
• mātra – merely, only, just
  indeclinable
• eka – one, single
  pronoun (masculine)
• sāmānya – commonness, generality, common property
  noun (neuter)
  Derived from 'samāna' (equal, same) + '-ya' suffix

Note: Explains the reason for the Self's uniformity.

इतरस्य (itarasya) - of anything other than pure existence (of the other)

(pronoun)

Genitive, masculine, singular of itara

itara - other, different, another

Note: Refers to anything other than pure existence.

अपि (api) - also, even, too

(indeclinable)

असंभवात् (asaṁbhavāt) - due to the impossibility, due to non-existence

(noun)

Ablative, masculine, singular of asaṃbhava

asaṁbhava - impossibility, non-existence

'a' prefix for negation, 'saṃbhava' meaning possibility/existence.

Compound type : Nañ-Tatpurusha (a+saṃbhava)

• a – not, non-, un-
  indeclinable
  Negative prefix
• saṃbhava – possibility, existence, birth, origin
  noun (masculine)
  Derived from root 'bhū' (to be, become) with upasarga 'sam'
  Prefix: sam
  Root: bhū (class 1)

Note: The reason for the Self's unique, undifferentiated nature.