vesting

Noun

 * 1)  The entitlement of an employee to receive the full benefit of a pension at normal retirement age or a reduced pension upon early retirement even upon change of employer before retirement.
 * 2)  The entitlement of an employee to exercise a stock option after a predetermined period of time.
 * 3) Cloth for making vests.
 * 4) A vest pattern.

Etymology
From. Equivalent to.

Noun

 * 1) fortification