The word pin-up, to hang something on the wall in English, refers to the original American mainstream of incredibly beautiful girls illustrations which were revealing a big sensuality from her gestures and poses. Later to the above mentioned illustrations were added authentic real beauties photographies that stood out as sexual icons of forced reference especially in the 40's and 50's decades.
Some of these women who posed as models managed to stand out as actresses or "burlesque" artists, a theatrical entertainment consisted of comic skits, short turns and sometimes striptease. Normally these photos turned out to be published in calendars and in so called "girlie magazines", publications of wide distribution among masculine public. In those days these girls, so much the real ones as the arisen ones from the imagination of some illustrators, were also known by the pseudonym of "cheesecakes" or "girls-next-door". To eat up them!
Normally the type of fashionable girl was not a very thin woman of seductive curves. Balance was the main beauty canon of the age, because extremes have never been good. Their stunning and spectacular appearances and a provocative "femme fatale" attitude were the main weapons of these women who took place of an important event of cultural relevance.