Styles of Mead

mead - honey wine (also tradtional mead)
sack mead - sweet mead (i.e. lots more honey)
bochet - burnt sack mead
bracket - mead and ale
cyser - mead with apple juice
melomel - mead with fruits other than apples or grapes
metheglin - mead with spices or herbs
morat - mead with mulberries
sack metheglin - sweet mead with spices or herbs
pyment - mead with grapes
rhodomel - rose-petal mead

Worth mentioning is soma of the ancient hindu writings. Soma is a mixture of juice from the pressed soma plant, milk and honey that has been allowed to ferment.