Rrarraa is a consonant of the Gurmukhi alphabet

Rrarraa is a consonant of the Gurmukhi script of Gurbani and identical to the Punjabi alphabet. Rraarraa is pronounced with the tongue curled back to touch just behind the ridge at the roof of the mouth and sounds like ra.
The Romanized spelling of Rraarraa is phonetic and may also appear spelled as Rhaarhaa. Spellings may differ slightly in original Gurmukhi as well as Romanized and English translations of Gurbani.
Sikh scripture includes the acrostic form of poetic verse featuring significance of Gurmukhi alphabet and appears throughout the Guru Granth Sahib.

Guru Nanak, first of the Sikh gurus, astonished his instructors when as a young boy given a homework assignment in school to write the alphabet, the child responded with a spiritual acrostic:

• "Rraarrai raarr kareh kiaa praanee tiseh dhiaavhu je amar hoaa ||
  RRARRA: Why quarrel O mortal? Meditate on the imperishable Lord." SGGS||434

Other acrostic verses in Gurbani include:

• "Rraarraa rraar mittai sang sadhoo ||
  RRARRA: Conflict is eliminated when associating with true the pious.
  
  Karam dharam tat naam araadhoo ||
  The essence of religious rites and creeds is meditation done in adoration of the Lord's Name.
  
  Roorho jih basiou ridh maahee ||
  In the heart of whom the Beauteous Lord abides,
  
  Ouaa kee rraarr mittat binsaahee ||
  Strife is erased, eliminated.
  
  Rraarr karat saakat gaavaaraa ||
  The opinionated argue foolishly in faithless disputes.
  
  Jaeh heeai ahnbudh bikaaraa ||
  Whose heart is filled with prideful intellect in ignorance bickers.
  
  Rraarraa gurmukh rraarr mittaaee ||
  RRARRA: Dispute is settled by the enlightened mouth which ceases to quarrel.
  
  Nimakh maahe naanak samjhaaee ||47||
  In an instant the Exalted instructor, O Nanak, is understood." Guru Arjun SGGS||260