A military pageant also includes a motorcycle race (6)
I believe the answer is:
tattoo
'a military pageant' is the definition.
(I've seen this before)
'also includes a motorcycle race' is the wordplay.
'also' becomes 'too' (synonyms).
'includes' is an insertion indicator.
'a motorcycle race' becomes 'att' (I can't justify this - if you can you should believe this answer much more).
'too' going around 'att' is 'TATTOO'.
(Other definitions for tattoo that I've seen before include "Skin design - military entertainment" , "drawing on arms, perhaps" , "one has to beat" , "made by drumming" , "Military pageant" .)