"Jock"

[Douglas G. Wilson]

>It seems to me that "jock" derives from "jockey strap", "jockey" being the
>trade name of a company which manufacters athletic supporters.  No date, must
>be early 20th.

I agree in part: "jock" = "athlete" < "jock" = "jockstrap" = "athletic
supporter". This transference occurred by the 1950's but I suppose it could
be older.

But "jockstrap" probably < "jock" = "penis", and "jockstrap" is old -- MW
says 1886.

"Jockey" as an underwear brand dates from 1934, I think (from a casual
glance at the USPTO database).

-- Doug Wilson