Incorrect on both counts.

1- Imbalance is a proper term and a common word. It's not just the "free" dictionary, open up ANY dictionary and look at it. The quoted definition is from Apple's own included dictionary application.
2- The T3 and K2x used on the OM6xx engines are NOT balanced together. This is evidenced by the fact the nut securing the compressor wheel on the shaft is unmodified.

You can tell how the balancing was done by the shape/appearance of the COMPRESSOR nut. If the nut appears to be ground down then the turbine wheel and shaft and the compressor wheel (and nut) were balanced together. If the nut is not ground down then the wheels were done individually. If the wheels were done individually then it is not absolutely necessary to mark them and get them in the same location as they were prior to removal. In the case of the "ground down nut" turbo, it is a good idea to keep the wheels lined up in their original positions.

http://www.gnttype.org/techarea/turbo/turborebuild.html