Text at top of page (6)
I believe the answer is:
header
'text at top of page' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for header that I've seen before include "Lines at top of page" , "Line at top of each page of a document" , "Line of text indicating what the passage below it is about" , "Text at top of page" , "One way to get a goal in football" .)