the top part of a girls boob.
show me some of your top boob
by rodney42 September 27, 2006
topboob is that bit of boob that you can basically see every time a girl is wearing something that shows off a bit of cleavage, a poor man's sideboob or/and underboob.
Oh. Oh well, topboob is topboob.
by beeeeeeeees June 21, 2011