The abbreviation "BTK" stands for different things depending on context:
- In criminal history, BTK stands for "Bind, Torture, Kill." This is the nickname of Dennis Rader, an American serial killer who murdered at least ten people in Wichita, Kansas, between 1974 and 1991. He named himself BTK after the method he used to kill his victims—binding, torturing, and killing them.
- In biology and medicine, BTK refers to Bruton tyrosine kinase, a protein involved in the development and maturation of B cells (a type of white blood cell). BTK inhibitors are substances that block this protein and are used in treating some cancers.
Other meanings of BTK include:
- Bacillus thuringiensis kurstaki, a bacterium used as an insecticide
- Below-the-knee amputation in medicine
- Bulgarian Telecommunications Company
- Baku–Tbilisi–Kars railway
- ISO codes for Batak languages
- Various music bands and songs named "BTK" or similar.
The most widely known meaning of BTK is related to the serial killer Dennis Rader, "Bind, Torture, Kill".
