Phonics glossary

Glossary of terms
The following terms and their definitions have been taken from Jim Rose's (2005) Independent Review of the Teaching of Early Reading - Interim Report.

blend (vb) — to draw individual sounds together to pronounce a word, e.g. s-n-a-p, blended together, reads snap
cluster — two (or three) letters making two (or three) sounds, e.g. the first three letters of 'straight' are a consonant cluster
(vowel) digraph — two letters making one sound, e.g. sh, ch, th, ph. Vowel digraphs comprise two vowels which, together, make one sound, e.g. ai, oo, ow
split digraph — two letters, split, making one sound, e.g. a-e as in make or i-e in site
grapheme — a letter or a group of letters representing one sound, e.g. sh, ch, igh, ough (as in 'though')
grapheme-phoneme correspondence (GPC) — the relationship between sounds and the letters which represent those sounds; also known as 'letter-sound correspondences'
mnemonic — a device for memorising and recalling something, such as a snake shaped like the letter 'S'
phoneme — the smallest single identifiable sound, e.g. the letters 'sh' represent just one sound, but 'sp' represents two (/s/ and /p/)
segment (vb) — to split up a word into its individual phonemes in order to spell it, e.g. the word 'cat' has three phonemes: /c/, /a/, /t/
VC, CVC, CCVC — the abbreviations for vowel-consonant, consonant-vowel-consonant, consonant-consonant-vowel-consonant, and are used to describe the order of letters in words, e.g. am, Sam, slam.

Another very useful glossary from the Jelly and Bean website

Jelly and Bean glossary