Shark can refer to
- Apple's performance analysis tool, "Shark" (currently part of "Instruments" application)
- S.Ha.R.K. (Soft Hard Real-time Kernel) - real-time OS kernel
- JIT compiler from OpenJDK's Zero project
- Wireshark, a network protocol analyzer for capturing and interactively browsing traffic on computer networks.
- Shark, a Hive-compatible large-scale data warehouse system based on Apache Spark.
The "Hive-compatible large-scale data warehouse system based on Apache Spark" seems to be the most common use at the moment, and should likely become the official use of this tag.
I am open to suggestions about the remaining two uses ("Soft Hard Real-time Kernel" and "OpenJDK Zero JIT compiler").