Dreams too about sports stadium (9)
I believe the answer is:
astrodome
'sports stadium' is the definition.
'astrodome' can be an answer for 'stadium' (I've seen this before). I'm not certain of the 'sports' bit.
'dreams too about' is the wordplay.
'about' is an anagram indicator.
'dreams'+'too'='dreamstoo'
'dreamstoo' with letters rearranged gives 'ASTRODOME'.
Can you help me to learn more?
(Other definitions for astrodome that I've seen before include "Sports centre covered by translucent hemispherical roof" , "Big American stadium" , "one would observe stars here" .)