Matroska (MKV) is surely an English word based on the Russian word matryoshka, so this means nesting doll (the regular Russian cylindrical-shaped doll within a doll, also known as a babushka doll). This is a experience the container (media in a kind of media/doll with a doll) part of the matryoshka which is a container for visual and audio data. The loose transliteration could possibly be confusing for Russian speakers, since the Russian word matroska actually refers to a sailor suit.
MKV is made with the future planned. It incorporates features you'd expect from a modern container format, like:
Fast seeking in the file
Full metadata (tags) support
Selectable subtitle/audio/video streams
Error resilience (can recover playback even when the stream is damaged)
Streamable over the internet and local networks (HTTP, CIFS, FTP, etc)
Menus (like DVD s have)
is an open standard project. This implies for personal use it is free to use and this the technical specifications describing the bitstream are open to everybody, even going to companies that might choose to support it of their products. The original source code of the libraries brought to life by the Matroska Team of developers is licensed under GNU L-GPL. Also, in addition there are free parsing and playback libraries available within the BSD license, for commercial software and hardware adoption.