Iri is the third letter of the Gurmukhi painti and the last of its three vowel bearers. Like Ura it is silent standing alone, and its whole function is to hold a vowel mark when a syllable opens with a vowel. The front vowels are assigned to it. The mark called sihari, written before the letter although read after it, gives i. Its long counterpart, bihari, written after, gives ee. A single stroke above, the lavan, gives e. The sihari is worth noting on its own account, because it is written to the left of the letter it belongs to while being pronounced after it, so a reader must take the mark and the letter as one unit rather than reading strictly left to right. That behaviour is inherited from the wider Brahmic family and it is the commonest early stumble in learning the script.
Iri is the narrowest of the three bearers, two short verticals dropped from the headline, and beginners regularly confuse it with the consonant Sassa, which is why primers drill the three bearers together as a block before introducing any consonant at all. Bare Iri does not appear as a word, for the same reason bare Ura does not: there is nothing for a bearer to say until something is written on it. The three bearers are also the clearest illustration of why Gurmukhi is classed as an abugida rather than an alphabet: the system assumes a consonant, and a vowel standing on its own is the exception that needs machinery.