Phonics refers to the understanding that there is a predictable relationship between phonemes (the sounds of spoken language) and graphemes (the letters and spellings that represent those sounds in written language). Also known as letter-sound or sound-symbol correspondences.

See also:
"Phonics" is in the UNSPSC Code "60101326"
  Phonics Flash cards

Other /More definition:
Phonics refers to the understanding that there is a predictable relationship between phonemes (the sounds of spoken language) and graphemes (the letters and spellings that represent those sounds in written language). Also known as letter-sound or sound-symbol correspondences.