An IC ID (sometimes abbreviated IC) on a cell phone is the regulatory certification number used to certify the cell phone complies to wireless emissions standards in Canada. Using the IC ID, you can lookup the wireless frequency the cell phone uses, the radiation you may be absorbing by using the cell phone, and other technical information about the device. IC IDs must be on all cell phones and other wireless transmitting devices certifying they are approved for use in Canada. The USA has a similar approval process which involves FCC IDs. Effectively, this makes the IC ID / IC the Canadian equivalent to the FCC ID.
South Korea has an equivalent process assigning KCC ID / MSIP.
China has an equivalent process assigning the CMIIT ID.