योगवासिष्ठः yogavāsiṣṭhaḥ - book-6, chapter-69, verse-40

एकार्थाभ्यसनप्राणरोधचेतःपरिक्षयाः ।
एकस्मिन्नेव संसिद्धे संसिद्ध्यन्ति परस्परम् ॥ ४० ॥

ekārthābhyasanaprāṇarodhacetaḥparikṣayāḥ ,
ekasminneva saṃsiddhe saṃsiddhyanti parasparam 40

40. ekārthābhyasana-prāṇarodha-cetaḥparikṣayāḥ
ekasmin eva saṃsiddhe saṃsiddhyanti parasparam

40. ekārthābhyasana-prāṇarodha-cetaḥparikṣayāḥ
ekasmin eva saṃsiddhe parasparam saṃsiddhyanti

40. The practices of focused meditation on a single object (ekārtha-abhyasana), breath control (prāṇarodha), and the complete dissolution of the mind (cetaḥparikṣayāḥ) — when any one of these is perfectly accomplished, they all become mutually perfected.

Words meanings summery:

• एकार्थाभ्यसन-प्राणरोध-चेतःपरिक्षयाः (ekārthābhyasana-prāṇarodha-cetaḥparikṣayāḥ) - the practices of focused meditation on a single object, breath control, and mind dissolution

• एकस्मिन् (ekasmin) - in one (of these practices) (in one, in a single one (masculine))

• एव (eva) - indeed, only, just, certainly

• संसिद्धे (saṁsiddhe) - when perfected, when accomplished, when fulfilled

• संसिद्ध्यन्ति (saṁsiddhyanti) - they become perfected, they are accomplished, they succeed

• परस्परम् (parasparam) - mutually, reciprocally, one another

Words meanings and morphology

एकार्थाभ्यसन-प्राणरोध-चेतःपरिक्षयाः (ekārthābhyasana-prāṇarodha-cetaḥparikṣayāḥ) - the practices of focused meditation on a single object, breath control, and mind dissolution

(noun)

Nominative, masculine, plural of ekārthābhyasanaprāṇarodhacetaḥparikṣaya

ekārthābhyasanaprāṇarodhacetaḥparikṣaya - the practices of single-pointed concentration, breath control, and mental dissolution

Compound type : dvandva (ekārthābhyasana+prāṇarodha+cetaḥparikṣaya)

• ekārthābhyasana – practice of concentrating on a single object
  noun (neuter)
• prāṇarodha – restraint of breath, breath control
  noun (masculine)
• cetaḥparikṣaya – dissolution/destruction of the mind (cetaḥ)
  noun (masculine)

एकस्मिन् (ekasmin) - in one (of these practices) (in one, in a single one (masculine))

(pronoun)

Locative, masculine, singular of eka

eka - one, a single, unique

एव (eva) - indeed, only, just, certainly

(indeclinable)

संसिद्धे (saṁsiddhe) - when perfected, when accomplished, when fulfilled

(adjective)

Locative, masculine, singular of saṃsiddha

saṁsiddha - perfected, accomplished, complete, successful

Past Passive Participle

Derived from root sidh (to succeed, be accomplished) with prefix sam.

Prefix: sam

Root: sidh (class 4)

संसिद्ध्यन्ति (saṁsiddhyanti) - they become perfected, they are accomplished, they succeed

(verb)

3rd person , plural, active, present indicative (laṭ) of saṃsidh

Prefix: sam

Root: sidh (class 4)

परस्परम् (parasparam) - mutually, reciprocally, one another

(indeclinable)