A grapheme is a written representation of a phoneme, for example: 'f', ''ph' and 'gh' (as in 'fat', 'photo' and 'tough') represent the same sound 'f'. Don't forget: a grapheme can only represent a single sound; otherwise, it is not a grapheme. Also, some phonemes can be represented by different graphemes, for example: the 'k' sound can be written with 'c', 'k' and 'ck'; the 'ee' can be be written with 'ee', 'ea', 'ie', 'ei', 'e' and 'ee'. Wow!
It might help if you say the words out loud. Once you have got to grips with this subject, move onto our 11-plus English Spelling: Phonemes quiz to give you an all-round understanding.
First, have a go at this quiz and see how good you are at spotting graphemes. Good luck!