رباعي

Relative adjective (nisba) composed of رُبَاع (rubāʕ, “four at a time”) +‎ ـِيّ (-iyy), from the root ر ب ع (r-b-ʕ); related to the numeral أَرْبَعَة (ʔarbaʕa, “four”).

رُبَاعِيّ • (rubāʕiyy) (feminine رُبَاعِيَّة (rubāʕiyya), masculine plural رُبَاعِيُّونَ (rubāʕiyyūna), feminine plural رُبَاعِيَّات (rubāʕiyyāt))

1. consisting of four, quadripartite, fourfold, quadruple
2. (geometry) quadrangular
3. (geometry) tetragonal
4. (grammar, linguistics) consisting of four radical letters, quadriliteral

• رُبَاعِيّ الأَضْلَاع (rubāʕiyy al-ʔaḍlāʕ), رُبَاعِيّ الْجَوَانِب (rubāʕiyy al-jawānib, “quadrilateral”)

رُبَاعِيّ • (rubāʕiyy) m, plural رُبَاعِيُّون (rubāʕiyyūn) or رُبَاعِيَّات (rubāʕiyyāt), feminine رُبَاعِيَّة (rubāʕiyya)

1. (sports) relay team of four
2. (music) quartet
3. (poetry) quatrain

The meaning “quatrain” uses the plural رُبَاعِيَّات (rubāʕiyyāt).

• Bengali: রুবাঈ (rubai)
• English: rubai
• Persian: رباعی (robâ'i)

• Wehr, Hans (1979) “ربع”, in J. Milton Cowan, editor, A Dictionary of Modern Written Arabic, 4th edition, Ithaca, NY: Spoken Language Services, →ISBN