When I was at Our Lady of Mercy Academy in 1983 the girls were required to wear slips under their dresses. They had two uniforms; the winter one was a plaid skirt but the summer one was a striped shirt dress that came in a variety of pastels that was nicknamed the handiwipe dress. At that time just about any lady wore a slip under her dress or skirt. It was about 95 or higher in my room one day when I was teaching Algebra II and I looked up and Shauna and MaryAnne had their slips on their heads like the nuns' veils. I laughed until I cried.
Just a few short years later in 1991 I was teaching English 1 at Holy Cross and there was a poem with a slip mentioned in it. None of my students knew what a slip was because by that time the girls were all wearing boxer shorts under their uniforms. I tried explaining it as a piece of lingerie but that fell on uncomprehending ears. Finally I resorted to something like it was a prettier garment that went under skirts and dresses before boxer shorts did. I almost flipped up a corner of my dress to show the lace but had second thoughts about the propriety of that.
I continued to wear them and panty hose for years no matter how hot my room was and sometimes it was 100 by 9 in the morning,until one day at lunch Sister Gil and I were talking and I said that I couldn't get them back up if I took them down so I was stuck; they were just glued to me and she said, "Get in the bathroom and take those things off before you die of heatstroke you fool." I did. It made sense and I gave up my strict adherence to unfashionable pantyhose at that point; that was probably around 2002, so you can see how long it took.