After reading Why is Data's uniform gold and not red? in which it is clearly stated that
Gold is operations (security, science, engineering, etc.), Red is command.
Why is Kirk dressed in Gold?
After reading Why is Data's uniform gold and not red? in which it is clearly stated that
Gold is operations (security, science, engineering, etc.), Red is command.
Why is Kirk dressed in Gold?
Per the DS9 episode "Trials and Tribble-ations";
"O'BRIEN: Don't you know anything about this period in time?
BASHIR: I'm a doctor, not an historian.
SISKO: In the old days, operations officers wore red, command officers wore gold.
DAX: And women wore less.
(Dax pirouettes. The red skirt suits her legs.)
BASHIR: I think I'm going to like history.

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The uniform colour semantics were changed between TOS and TNG. Gold indicated command in TOS and red indicated "likely to die soon" .. err ... Operations.