Sigma/upsilon go-between
I believe the answer is:
tau
(Other definitions for tau that I've seen before include "letter from foreigner" , "Letter from Greece" , "Homeric character" , "Greek letter; cross" , "Greek character" .)
I believe the answer is:
tau
(Other definitions for tau that I've seen before include "letter from foreigner" , "Letter from Greece" , "Homeric character" , "Greek letter; cross" , "Greek character" .)