महाभारतः mahābhārataḥ - book-12, chapter-202, verse-20

ततो देवादिदेवः स योगात्मा योगसारथिः ।
योगमास्थाय भगवांस्तदा भरतसत्तम ॥२०॥

20. tato devādidevaḥ sa yogātmā yogasārathiḥ ,
yogamāsthāya bhagavāṁstadā bharatasattama.

20. tataḥ devādidevaḥ saḥ yogātmā yogasārathiḥ
| yogam āsthāya bhagavān tadā bharatasattama

20. bharatasattama,
tataḥ saḥ devādidevaḥ yogātmā yogasārathiḥ bhagavān tadā yogam āsthāya.
.
.

20. O best among the Bhāratas, then that God of gods, whose very self (ātman) is contemplation (yoga) and who is the guide of contemplation (yoga), having resorted to his divine power (yoga), the venerable one, at that moment...

Words meanings summery:

• ततः (tataḥ) - then (then, thereupon, from that)

• देवादिदेवः (devādidevaḥ) - the supreme God (referring to Vishnu/Kṛṣṇa) (God of gods, the supreme deity)

• सः (saḥ) - that (God of gods) (he, that)

• योगात्मा (yogātmā) - whose very self (ātman) is contemplation (yoga) (whose essence is yoga, whose soul is yoga, embodying yoga)

• योगसारथिः (yogasārathiḥ) - the guide of contemplation (yoga) (charioteer of yoga, guide of yoga)

• योगम् (yogam) - his divine power (yoga) (union, spiritual discipline, means, mystic power)

• आस्थाय (āsthāya) - having resorted to, having taken recourse to (having resorted to, having adopted, having taken recourse to)

• भगवान् (bhagavān) - the venerable one, the Lord (venerable, divine, glorious, the lord)

• तदा (tadā) - at that moment (then, at that time)

• भरतसत्तम (bharatasattama) - O best among the Bhāratas (a traditional epithet for kings like Janamejaya in the Mahabharata) (O best of Bharatas)

Words meanings and morphology

ततः (tataḥ) - then (then, thereupon, from that)

(indeclinable)

Adverbial form from pronominal stem 'tad'.

देवादिदेवः (devādidevaḥ) - the supreme God (referring to Vishnu/Kṛṣṇa) (God of gods, the supreme deity)

(noun)

Nominative, masculine, singular of devādideva

devādideva - God of gods, the supreme deity

Compound type : tatpuruṣa (deva+ādi+deva)

• deva – god, deity
  noun (masculine)
• ādi – beginning, prime, first
  noun (masculine)
• deva – god, deity
  noun (masculine)

Note: Refers to Vishnu.

सः (saḥ) - that (God of gods) (he, that)

(pronoun)

Nominative, masculine, singular of tad

tad - that, he, she, it

Note: Pronominal adjective.

योगात्मा (yogātmā) - whose very self (ātman) is contemplation (yoga) (whose essence is yoga, whose soul is yoga, embodying yoga)

(adjective)

Nominative, masculine, singular of yogātman

yogātman - whose nature/self is yoga, embodying yoga, whose soul is yoga

Compound type : bahuvrīhi (yoga+ātman)

• yoga – union, connection, spiritual discipline, contemplation
  noun (masculine)
  Root: yuj (class 7)
• ātman – self, soul, spirit, essence, breath
  noun (masculine)

Note: Qualifies 'devādidevaḥ'.

योगसारथिः (yogasārathiḥ) - the guide of contemplation (yoga) (charioteer of yoga, guide of yoga)

(adjective)

Nominative, masculine, singular of yogasārathi

yogasārathi - charioteer of yoga, guide of yoga

Compound type : tatpuruṣa (yoga+sārathi)

• yoga – union, connection, spiritual discipline, contemplation
  noun (masculine)
  Root: yuj (class 7)
• sārathi – charioteer, driver, guide, leader
  noun (masculine)

Note: Qualifies 'devādidevaḥ'.

योगम् (yogam) - his divine power (yoga) (union, spiritual discipline, means, mystic power)

(noun)

Accusative, masculine, singular of yoga

yoga - union, connection, spiritual discipline, contemplation, means, method, application, mystic power

From root √yuj (to join).

Root: yuj (class 7)

Note: Object of 'āsthāya'.

आस्थाय (āsthāya) - having resorted to, having taken recourse to (having resorted to, having adopted, having taken recourse to)

(indeclinable)

absolutive

Derived from root √sthā (to stand) with prefix ā- (towards) and the suffix -ya (absolutive for prefixed verbs).

Prefix: ā

Root: sthā (class 1)

भगवान् (bhagavān) - the venerable one, the Lord (venerable, divine, glorious, the lord)

(adjective)

Nominative, masculine, singular of bhagavat

bhagavat - venerable, glorious, divine, fortunate; the Lord (often applied to Vishnu, Krishna, Buddha)

Note: Qualifies 'devādidevaḥ'.

तदा (tadā) - at that moment (then, at that time)

(indeclinable)

Adverbial form from pronominal stem 'tad'.

भरतसत्तम (bharatasattama) - O best among the Bhāratas (a traditional epithet for kings like Janamejaya in the Mahabharata) (O best of Bharatas)

(noun)

Vocative, masculine, singular of bharatasattama

bharatasattama - best of Bharatas, O chief of Bharatas

Compound type : tatpuruṣa (bharata+sattama)

• bharata – a descendant of Bharata, a king of the Lunar Dynasty
  proper noun (masculine)
• sattama – best, most excellent
  adjective (masculine)
  Superlative suffix -tama.

Note: Vocative address.