महाभारतः mahābhārataḥ - book-1, chapter-158, verse-18

इयं भूत्वा चैकवप्रा शुचिराकाशगा पुनः ।
देवेषु गङ्गा गन्धर्व प्राप्नोत्यलकनन्दताम् ॥१८॥

18. iyaṁ bhūtvā caikavaprā śucirākāśagā punaḥ ,
deveṣu gaṅgā gandharva prāpnotyalakanandatām.

18. iyam bhūtvā ca eka-vapra śuciḥ ākāśa-gā punaḥ
deveṣu gaṅgā gandharva prāpnoti alakanandatām

18. And this Gaṅgā, O Gandharva, having once flowed as a single-banked (single-streamed) and pure river through the sky, again attains the state of Alakanandā among the gods.

Words meanings summery:

• इयम् (iyam) - Refers to the Gaṅgā. (this (feminine))

• भूत्वा (bhūtvā) - having become

• च (ca) - and

• एक-वप्र (eka-vapra) - Describes the Gaṅgā as a single river before dividing or as it was in the past. (having one bank, single-streamed)

• शुचिः (śuciḥ) - pure, clean, sacred

• आकाश-गा (ākāśa-gā) - Refers to the Gaṅgā flowing in the celestial regions. (sky-goer, flowing in the sky)

• पुनः (punaḥ) - again, further, moreover

• देवेषु (deveṣu) - among the gods, in the gods

• गङ्गा (gaṅgā) - the Gaṅgā river

• गन्धर्व (gandharva) - Arjuna is addressing a Gandharva (celestial musician). (O Gandharva)

• प्राप्नोति (prāpnoti) - obtains, reaches, attains

• अलकनन्दताम् (alakanandatām) - Refers to the celestial river Alakanandā. (the state of Alakanandā)

Words meanings and morphology

इयम् (iyam) - Refers to the Gaṅgā. (this (feminine))

(pronoun)

Nominative, feminine, singular of idam

idam - this

भूत्वा (bhūtvā) - having become

(indeclinable)

Absolutive (Gerund)

from root bhū with -tvā suffix

Root: bhū (class 1)

च (ca) - and

(indeclinable)

एक-वप्र (eka-vapra) - Describes the Gaṅgā as a single river before dividing or as it was in the past. (having one bank, single-streamed)

(adjective)

Nominative, feminine, singular of eka-vapra

eka-vapra - having one bank/shore; single-streamed

Compound type : bahuvrīhi (eka+vapra)

• eka – one, single, unique
  numeral (masculine)
• vapra – bank, shore, dyke, mound
  noun (masculine)

Note: Agrees with 'iyam Gaṅgā'

शुचिः (śuciḥ) - pure, clean, sacred

(adjective)

Nominative, feminine, singular of śuci

śuci - pure, bright, clean, sacred

Note: Agrees with 'iyam Gaṅgā'

आकाश-गा (ākāśa-gā) - Refers to the Gaṅgā flowing in the celestial regions. (sky-goer, flowing in the sky)

(adjective)

Nominative, feminine, singular of ākāśa-ga

ākāśa-ga - moving in the sky, celestial (used for rivers, birds etc.)

Compound type : upapada-tatpuruṣa (ākāśa+ga)

• ākāśa – sky, ether, space
  noun (masculine)
• ga – going, moving
  adjective (masculine)
  Agent noun/suffix
  From root gam (to go) + suffix -a
  Root: gam (class 1)

Note: Feminine form of ākāśaga, agrees with 'iyam Gaṅgā'.

पुनः (punaḥ) - again, further, moreover

(indeclinable)

देवेषु (deveṣu) - among the gods, in the gods

(noun)

Locative, masculine, plural of deva

deva - god, deity, celestial being

गङ्गा (gaṅgā) - the Gaṅgā river

(proper noun)

Nominative, feminine, singular of gaṅgā

gaṅgā - the Gaṅgā river (Ganges)

गन्धर्व (gandharva) - Arjuna is addressing a Gandharva (celestial musician). (O Gandharva)

(proper noun)

Vocative, masculine, singular of gandharva

gandharva - Gandharva (a class of celestial beings, often musicians or singers)

प्राप्नोति (prāpnoti) - obtains, reaches, attains

(verb)

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

Present Active

Root āp (class 5) with prefix pra

Prefix: pra

Root: āp (class 5)

अलकनन्दताम् (alakanandatām) - Refers to the celestial river Alakanandā. (the state of Alakanandā)

(noun)

Accusative, feminine, singular of alakanandatā

alakanandatā - the state or condition of being Alakanandā

From alakanandā (proper noun, name of a celestial river) + -tā (suffix for abstract noun)