ADJ

whole
the whole realm of human intellect
new
international
public
domestic, private
political, social, spiritual

VERB + REALM

be/lie in, belong in/to
open up
The research has opened up new realms for investigation
enter, move into
descend into/to
(disapproving) Most readers are likely to lose interest when he descends into the realms of (= starts discussing) rhetorical terminology
move from/out of
The euro has moved from the realms of theory into reality

PREP

beyond/out of/outside the ~ of
His ambitions are way beyond the realms of possibility
in/within the ~ of
The idea belongs in the realm of science fiction

PHRASES

the realms of fantasy/possibility

VERB + REALM

defend
They fought to defend the realm

PREP

beyond/outside the ~
wealth acquired outside the realm
in/within the ~
peace within the realm
throughout the ~
There was rejoicing throughout the realm

PHRASES

a part of the realm, the defence of the realm
Royal taxation usually had to be for the defence of the realm