Eg, physics (7)
I believe the answer is:
science
'eg physics' is the definition.
(physics is a kind of science)
This is the entire clue.
(Other definitions for science that I've seen before include "The search for facts" , "Eg, botany or physics" , "Physics or chemistry, say" , "Subject such as biology, physics, etc" , "Study of physical things by observation and experiment" .)