Meaning
The lip.
Literally: lip
How Iqbal uses it
Lab is the beloved's lip — source of the smile, the word, the longed-for kiss, often painted red as wine or ruby. In the ghazal the lip both gives life (its speech, its smile) and withholds it (its silence, its refusal). Sufi poets prize the lip as the seat of the life-giving word and breath, the place from which the Beloved's grace, or its cruel silence, issues.
See it in the verse
Lab in Iqbal’s couplets
Lab pe aati hai dua ban ke tamanna meri
Zindagi shama ki surat ho khudaya meri
Zindagi shama ki surat ho khudaya meri
My longing rises to my lips as a prayer: O God, may my life be like a candle's flame.
Hope · Aspiration
Be-khatar kud pada aatish-e-Nimrood mein ishq
Aql hai mahv-e-tamasha-e-lab-e-baam abhi
Aql hai mahv-e-tamasha-e-lab-e-baam abhi
Love leapt fearlessly into the fire — while reason still stood on the rooftop's edge, lost in watching the spectacle.
Courage · Love · Action
Aankh jo kuchh dekhti hai lab pe aa sakta nahin
Mahv-e-hairat hoon ki duniya kya se kya ho jaegi
Mahv-e-hairat hoon ki duniya kya se kya ho jaegi
What the eye sees cannot be brought to the lips; I am lost in wonder at what this world is about to become.
Awakening · Aspiration