योगवासिष्ठः yogavāsiṣṭhaḥ - book-2, chapter-18, verse-66

एकदेशसमर्थत्वादुपमेयावबोधनम् ।
उपमानं करोत्यङ्ग दीपोऽर्थप्रभया यथा ॥ ६६ ॥

ekadeśasamarthatvādupameyāvabodhanam ,
upamānaṃ karotyaṅga dīpo'rthaprabhayā yathā 66

66. ekadeśasamarthatvāt upameyāvabodhanam upamānam
karoti aṅga dīpaḥ arthaprabhayā yathā

66. aṅga ekadeśasamarthatvāt upameyāvabodhanam
upamānam karoti yathā dīpaḥ arthaprabhayā

66. O dear one, just as a lamp illuminates objects (artha) by its light, so too a comparison (upamāna), by being effective in one aspect (ekadeśa), brings about the comprehension of the object being compared (upameya).

Words meanings summery:

• एकदेशसमर्थत्वात् (ekadeśasamarthatvāt) - due to the capability in one part, on account of effectiveness in a single aspect

• उपमेयावबोधनम् (upameyāvabodhanam) - the comprehension of the object to be compared, understanding the upameya

• उपमानम् (upamānam) - the object of comparison, the standard of comparison

• करोति (karoti) - does, makes, causes

• अङ्ग (aṅga) - O dear one, O friend, indeed, certainly (vocative particle or interjection)

• दीपः (dīpaḥ) - a lamp, light

• अर्थप्रभया (arthaprabhayā) - by the light for objects, by the light illuminating objects

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

Words meanings and morphology

एकदेशसमर्थत्वात् (ekadeśasamarthatvāt) - due to the capability in one part, on account of effectiveness in a single aspect

(noun)

Ablative, neuter, singular of ekadeśasamarthatva

ekadeśasamarthatva - the state of being capable/effective in one part/aspect

Abstract noun formed from 'ekadeśasamartha' + suffix '-tva'. 'Ekadeśasamartha' is a compound.

Compound type : tatpuruṣa (ekadeśa+samartha+tva)

• eka – one, single
  numeral
• deśa – part, region, country
  noun (masculine)
  From root diś- 'to point out'
  Root: diś (class 6)
• samartha – capable, able, effective, suitable
  adjective (masculine)
  From sam- + artha (meaning/purpose, from root ṛ- 'to go')
  Prefix: sam
  Root: ṛ (class 1)
• tva – suffix for abstract noun, -ness, -hood
  suffix (neuter)
  Forms abstract nouns from adjectives or nouns.

उपमेयावबोधनम् (upameyāvabodhanam) - the comprehension of the object to be compared, understanding the upameya

(noun)

Accusative, neuter, singular of upameyāvabodhana

upameyāvabodhana - understanding of the upameya (object of comparison)

Compound of 'upameya' (object to be compared) and 'avabodhana' (understanding).

Compound type : ṣaṣṭhī-tatpuruṣa (upameya+avabodhana)

• upameya – object to be compared, subject of comparison
  noun (neuter)
  Gerundive / Future Passive Participle
  From upa- + root mā (to measure) + -eya
  Prefix: upa
  Root: mā (class 2)
• avabodhana – understanding, comprehension, instruction
  noun (neuter)
  From ava- + budh (to know) + -ana
  Prefix: ava
  Root: budh (class 1)

Note: Object of karoti.

उपमानम् (upamānam) - the object of comparison, the standard of comparison

(noun)

Nominative, neuter, singular of upamāna

upamāna - object of comparison, standard of comparison, analogy

From root mā (to measure) with prefix upa- and suffix -ana.

Prefix: upa

Root: mā (class 2)

Note: Subject of karoti.

करोति (karoti) - does, makes, causes

(verb)

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

Present tense, active voice

3rd person singular, present indicative, active voice.

Root: kṛ (class 8)

अङ्ग (aṅga) - O dear one, O friend, indeed, certainly (vocative particle or interjection)

(indeclinable)

Often used as an address.

Note: Functions as a vocative particle here.

दीपः (dīpaḥ) - a lamp, light

(noun)

Nominative, masculine, singular of dīpa

dīpa - lamp, light

From root dīp- 'to shine'.

Root: dīp (class 4)

Note: Subject in the yathā clause.

अर्थप्रभया (arthaprabhayā) - by the light for objects, by the light illuminating objects

(noun)

Instrumental, feminine, singular of arthaprabhā

arthaprabhā - light of objects, light for objects, radiant object

Compound of 'artha' (object) and 'prabhā' (light, radiance).

Compound type : ṣaṣṭhī-tatpuruṣa (artha+prabhā)

• artha – object, thing, purpose, meaning
  noun (masculine)
• prabhā – light, radiance, splendor
  noun (feminine)
  From pra- + bhā (to shine)
  Prefix: pra
  Root: bhā (class 2)

Note: Means by means of light.

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

(indeclinable)

Correlative to tathā.