Letters (4)
'letters' is the definition.
(letters sent in the post or mail)
This is all the clue.
(Other definitions for mail that I've seen before include "Eg, letters" , "letter?" , "protective cover" , "Letters - armour" , "Chain armour" .)
(Other definitions for abcs that I've seen before include "Know these to be well versed - alphabetically?" , "12 [THINGS EASY]" , "guides ..." , "Know these letters to be well informed" .)
'letters' is the definition.
(I've seen this in another clue)
This is all the clue.
'letters' is the definition.
(I know this)
This is all the clue.
(Another definition for consonants that I've seen is " Letters".)