Specifically, I think, the tan color of summer uniforms in the U.S.
Army, as Horace mentioned.
"Instead of Imperial Austrian officers in sky-blue tunics, there are
now American GIs in suntans but otherwise nothing has changed."
/Esquire/, 1955
"Regular uniforms for enlisted men were olive drab in the spring and
winter months, suntans in the warm weather. Officers generally wore
pinks with dress coats, and suntans in the summer."
/Life of the Soldier and the Airman: Volumes 27-28/, 1945
Or pants of that color for civilians.
"The formally attired Italian businessman can never be convinced that
these boys wear suntans or blue jeans because they cannot afford
better."
/The Reporter/, 1949
"Suntans are most popular in the classroom. The umbrella has become
quite popular with the men of late. 'For men, campus wear generally
consists of suntans or cords [corduroy pants] for classes, with sport
shirts or wool shirts and jacket.'"
/Men's Wear/, 1961
I believe they /were/ popular in the classroom. My alumni magazine
once carried a picture of a lecture from around 1960. As I remember,
the hall is full of nearly identical young white men, all wearing
creased tan pants and white dress shirts, except one iconoclast who is
wearing creased tan pants and a white T-shirt.
--
Jerry Friedman