eSIM - Computer Definition
(Embedded SIM) A chip that is equivalent in function to a Mini or Micro SIM card used to identify the telephone number in a cellphone. With the traditional SIM card, changing phone numbers or carriers requires replacing the card in the SIM tray. However, an embedded SIM can be reprogrammed by software. eSIMs are also used in wireless machine-to-machine devices that have permanent identities. See SIM card.