End of Active Service (EAS) is the conclusion of the period of active duty commitment for a member of the United States military.
This date can be changed by reenlistment, extension, retirement, renewal of active orders, and administrative separation, among other things. This is not to be confused with Expiration of Current Contract (ECC) or Expiration of Obligated Service (EOS).
References
End Of Active Service Wikipedia(Text) CC BY-SA