Vesting is just receiving the full rights of the share, option, or whatever over a specific amount of time. If you start a company with someone you don't (er,

Vesting is just receiving the full rights of the share, option, or whatever over a specific amount of time. If you start a company with someone you don't (er, shouldn't) just automatically get 50% of the company. That would allow you walk on day 3 and still own 50%. Instead you receive the ability to leave with your shares on a vesting schedule so that you have skin in the game.