Ring out, ring in, I will get you the runs... (7)
I believe the answer is:
calomel
'you the runs' is the definition.
I can't tell whether this definition defines the answer.
'ring out ring in i' is the wordplay.
'ring' becomes 'call' (synonyms).
'out' means one lot of letters goes inside another.
'ring in' becomes 'o' (letter resembling a ring. I am not sure about the 'in' bit.).
'i' becomes 'me'.
'o'+'me'='ome'
'call' going around 'ome' is 'CALOMEL'.
'will get' acts as a link.
Can you help me to learn more?
(Another definition for calomel that I've seen is " All come (anag) - purgative".)