यद्

यद्

1. Devanagari script form of yad, which is neuter nominative and accusative singular of य (ya, “which (relative)”)

From Proto-Indo-Aryan *Hyás, from Proto-Indo-Iranian *Hyás, from Proto-Indo-European *Hyós, *Hyéh₂, *Hyód (“who, which”). Cognate with Ancient Greek ὅς (hós), ἥ (hḗ), ὅ (hó), Avestan 𐬫𐬋‎ (yō), Phrygian ιος (yos), Old Church Slavonic иже (i-že), Lithuanian jis, ji.

• (Vedic) IPA^(key): /jɐ́d̪/
• (Classical) IPA^(key): /jɐd̪/

यद् • (yád)

1. who, which, what, whichever, whatever, that (RV. etc.)

Usually with correlatives तद् (tad), त्यद् (tyad), एतद् (etad), इदम् (idam), अदस् (adas), तद् एतद् (tad etad), एतद् त्यद् (etad tyad), इदं तद् (idaṃ tad), तद् इदम् (tad idam), तादृश (tādṛśa), ईदृश (īdṛśa), ईदृश् (īdṛś), एतावद् (etāvad), by which it is oftener followed than preceded, or the correlative is dropped e.g.

yas tu nā*rabhate karma kṣipram bhavati nirdravyaḥ - [he] indeed who does not begin work soon becomes poor (R.)

or the relative pronoun is dropped e.g.

andhakam bhartāraṃ na tyajet sā mahā-satī - she who does not desert a blind husband is a very faithful wife (Vet.)

yad is often repeated to express "whoever", "whatever", "whichever", e.g.

yo yaḥ - whatever man

yā yā - whatever woman

yo yaj jayati tasya tat - whatever he wins (in war) belongs to him (Mn. VII, 96)

yad yad vadati tad tad bhavati - whatever he says is true

or the two relatives may be separated by हि (hi), and are followed by the doubled or single correlative तद् (tad) e.g.

upyate yad dhi yad bījam tat tad eva prarohati - whatever seed is sown, that even comes forth (Mn. IX, 40)

Similar indefinite meanings are expressed by the relative joined with तद् (tad) e.g.

yasmai tasmai - to any one whatever

especially in:

yadvā tadvā - anything whatever

or by यः (yaḥ) with कश्च (kaśca), कश्चन (kaścana), कश्चित् (kaścit), or (in later language, not in Manu) ko'pi e.g.

yaḥ kaścit - whosoever

yāni kāni ca mitrāṇi - any friends whatsoever

yena kenā*py upā*yena - by any means whatsoever

yad is joined with त्वद् (tvad) to express generalization e.g.

śūdrāṃs tvad yāṃs tvad - either the śūdras or anybody else (ŚBr.)

or immediately followed by a personal pronoun on which it lays emphasis e.g.

yo 'ham - I that very person who

yas tvaṃ kathaṃ vettha - how do you know? (ŚBr.)

It is also used in the sense of "si quis" e.g.

striyaṃ spṛśed yaḥ - should any one touch a woman

yad is also used without the copula e.g.

andho jaḍaḥ pīṭha sarpī saptatyā sthaviraśca yaḥ - a blind man, an idiot, a cripple, and a man seventy years old (Mn. VIII, 394)

Sometimes there is a change of construction in such cases e.g ye ca mānuṣāḥ for mānuṣāṃś-ca (Mn. X, 86).
The nominative singular neuter yad is then often used without regard to gender or number and may be translated by "as regards", "as for", e.g.

kṣatraṃ vā etad vanaspatīnāṃ yan nyag-rodhaḥ - as for the nyag-rodha, it is certainly the prince among trees (AitBr.)

or by "that is to say", "to wit" e.g.

tato devā etaṃ vajraṃ dadṛśur yad apaḥ - the gods then saw this thunderbolt, to wit, the water (ŚBr.)

yad as an adverbial conjunction generally means "that", especially after verbs of saying, thinking etc., often introducing an oratio directa with or without इति (iti); iti yad, at the end of a sentence = "thinking that", "under the impression that" e.g. Ratnāv. ii, 2÷8.
yad can also mean "so that", "in order that", "wherefore", "whence", "as", "in as much as", "since", "because" (the correlative being तद् (tad), "therefore"), "when", "if" RV. etc.

ádha yád - even if, although (RV.)

yad api - id. (Megh.

yad u - evam - as - so (ŚvetUp.)

yad uta - that (Bālar.), that is to say, scilicet (Kāraṇḍ., DivyĀv.)

yat kila - that (Prasannar.)

yac ca - if, that is to say (Car.)

yac ca-yac ca - both - and (DivyĀv.); that

According to Pāṇ.. 3-3, 148 after expressions of "impossibility", "disbelief", "hope", "disregard", "reproach" and, "wonder":

yad vā - or else (often found in commentators), whether (Kāv., Rājat.), however (Bālar.)

yad vā - yadi vā - if-or it (Bhag.)

yad bhūyasā - for the most part (DivyĀv.)

yat satyam - certainly, indeed, of course (Mṛicch., Ratnāv.)

yan nu, with 1st person - what if I, let me (DivyĀv.)

• Monier Williams (1899), “यद्”, in A Sanskrit–English Dictionary, […], new edition, Oxford: At the Clarendon Press, OCLC 458052227, page 0844.