1. The molecule being painstakingly sequenced during the Human Genome Project
. This molecule contains all the instructions necessary to program an entire human being, starting from a single cell.
2. The abbreviation for "deoxyribonucleic acid," or "deoxyribose nucleic acid", the deabbreviations of which are misspelt by pretty much anyone who isn't a scientist, a science teacher, or a nerdy student obsessed with science (I'm in the latter category).
3. "Data Not Available" - This is used to duck questions in a "funny" way, especially by the people who don't pay attention in class, but want to sound smart(er than they really are?).
Science Teacher: What is DNA?
Student: Data Not Available.
Science Teacher: You have to pay attention in class, then.
Later that day...
Mother: How do you spell the de-abbreviation of "DNA"?
Student: dioxiribonuicliec acid
Mother: And you are thinking of majoring in molecular biology
Student: What's with the frequent mentioning of the word "DNA" all of a sudden?