1. Nainsook is a fine, soft muslin fabric, often to used to make babies' clothing.

2. A soft, light cotton material, often with a woven stripe.

3. A fine fabric used for tucked or embroidered, blouses, night wear, lingerie, and infant's wear.

Beyond the meaning

From Hindi nainsukh, pleasant : nain, eye (from Sanskrit nayanam, from nayati, he leads) + sukh, pleasure (from Sanskrit sukha-, running easily (of chariots), pleasant : su-, good; see (e)su- in Indo-European roots + kham, opening, axle-hole in the nave of a wheel)