Vṛddhi

Vṛddhi (Sanskrit: वृद्धि, IPA: [ˈʋr̩d̪d̪ʰi]) is a Sanskrit word meaning 'growth' (from Proto-Indo-European *werdʰ- 'to grow').

In Pāṇini's Sanskrit grammar, it is a technical term for long vowels produced by ablaut (vowel gradation), as for example in:

In modern Indo-European linguistics it is used in Pāṇini's sense, but not restricted to Sanskrit but applicable to the Indo-European languages in general as well as to the Proto-Indo-European (PIE) language from which this feature was probably inherited:

Vṛddhi-derivations

A vṛddhi-derivation or vṛddhi-derivative is a word that is derived by such lengthening, a type of formation very common in Sanskrit, but also attested in other languages. Such derivatives signify "of, belonging to, descended from". An example: