योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-112, verse-15

विवेकैकानुसंधानाच्चिदंशात्मतया मनः ।
चिदेकतामुपायाति दृढाभ्यासवशादिह ॥ १५ ॥

vivekaikānusaṃdhānāccidaṃśātmatayā manaḥ ,
cidekatāmupāyāti dṛḍhābhyāsavaśādiha 15

15. vivekaikānusandhānāt cid-amśa-ātmatayā manaḥ
| cit-ekatām upāyāti dṛḍhābhyāsavaśāt iha ||

15. iha manaḥ vivekaikānusandhānāt cid-amśa-ātmatayā dṛḍhābhyāsavaśāt cit-ekatām upāyāti.

15. Here, through the singular contemplation of discernment (viveka) and by the nature of its conscious part, the mind (manas) attains oneness with consciousness (cit) due to strong and persistent practice.

Words meanings summery:

• विवेकैकानुसन्धानात् (vivekaikānusandhānāt) - from/through the singular contemplation of discernment

• चिद्-अम्श-आत्मतया (cid-amśa-ātmatayā) - by the nature of its conscious part

• मनः (manaḥ) - mind

• चित्-एकताम् (cit-ekatām) - oneness with consciousness

• उपायाति (upāyāti) - attains, approaches

• दृढाभ्यासवशात् (dṛḍhābhyāsavaśāt) - from/through the power of strong practice

• इह (iha) - here, in this world/context

Words meanings and morphology

विवेकैकानुसन्धानात् (vivekaikānusandhānāt) - from/through the singular contemplation of discernment

(noun)

Ablative, neuter, singular of vivekaikānusandhāna

vivekaikānusandhāna - singular contemplation of discernment

Compound type : tatpuruṣa (vivekaika+anusandhāna)

• vivekaika – singular discernment, unique discernment
  adjective
• anusandhāna – investigation, contemplation, diligent search
  noun (neuter)
  action noun
  Prefixes: anu+sam
  Root: dhā (class 3)

चिद्-अम्श-आत्मतया (cid-amśa-ātmatayā) - by the nature of its conscious part

(noun)

Instrumental, feminine, singular of cid-amśa-ātmatā

cid-amśa-ātmatā - the state of being a conscious part, having the nature of a conscious part

Derived from `cid-amśa-ātman` with suffix `tā` (abstract feminine noun)

Compound type : tatpuruṣa (cit-amśa+ātmatā)

• cit-amśa – a part of consciousness
  noun
• ātmatā – selfhood, nature (ātman), essential quality
  noun (feminine)
  Derived from `ātman` with suffix `tā` (abstract feminine noun)

मनः (manaḥ) - mind

(noun)

Nominative, neuter, singular of manas

manas - mind, intellect, heart

चित्-एकताम् (cit-ekatām) - oneness with consciousness

(noun)

Accusative, feminine, singular of cit-ekatā

cit-ekatā - oneness with consciousness

Compound type : tatpuruṣa (cit+ekatā)

• cit – consciousness, intelligence, mind
  noun (feminine)
• ekatā – oneness, unity, identity
  noun (feminine)
  Derived from `eka` (one) with suffix `tā` (abstract feminine noun)

उपायाति (upāyāti) - attains, approaches

(verb)

3rd person , singular, active, present indicative (laṭ) of yā

Prefixes: upa+ā

Root: yā (class 2)

दृढाभ्यासवशात् (dṛḍhābhyāsavaśāt) - from/through the power of strong practice

(noun)

Ablative, masculine, singular of dṛḍhābhyāsavaśa

dṛḍhābhyāsavaśa - control/sway of strong practice

Compound type : ṣaṣṭhī-tatpuruṣa (dṛḍhābhyāsa+vaśa)

• dṛḍhābhyāsa – strong practice
  noun
• vaśa – control, sway, power, means
  noun (masculine)

इह (iha) - here, in this world/context

(indeclinable)