The Urdu word "Sabaat" (ثبات) means:

Stability, steadiness, permanence, or consistency.

In poetic usage, it often refers to something being unchanging or firm.

In the poem:

"Teri soorat se hai aalam mein baharon ko sabaat"
"From your face, the springtime in the world finds its stability."

Here, "sabaat" implies that the beauty and constancy of spring in the world is because of the beloved’s presence or face. It suggests that the beloved brings lasting beauty and meaning to life.