Hiya,
Since so many lay people (myself included) don't understand the word poomsae, is it acceptable to say "Taekwon-DO patterns"?
Yes.
Don't use kata in reference to taekwon-do (or taekwondo) stuff.
My taekwon-do teacher was so surprised to find out that my step-dad (who is Japanese) was allowing me to take a Korean art. Japanese and Korean do not have a friendly history. (Yes, I know Karate isn't neccarily Japanese, but Okinawan.....)
OOOH! I love this story!!! (Me looks for another part).