Well according to my knowledge pink slip is one in which a employee is asked to leave the company. This is told by the company to employee . Also depending on company's rules and regulation thy give salary for some time to employee till he gets employed.

For ex if a Pink slip is given to particular Employee then HR team will tell the employee tht he dont need to come to office tomorrow but they will give him full salary for 2 months and he will be employed for 2months but need not come to office.. or he can be employed of a particular company for 4 months withdrawing half salary for 4 months..

Got it or stil not clear?