gStrings is a chromatic tuner application measuring sound pitch and intensity. This is the ad supported version.
It will let you tune any musical instrument (violin, viola, violoncello, bass, guitar, piano, wind instruments, your own voice/singing).
Features include:
1. multiple built-in instruments and tunings,
2. support for user-defined custom tunings,
3. a long list of built-in temperaments (just, pythagorean, meantone, comma, etc.),
4. support for user-defined custom temperaments,
5. orchestra tuning (shifting/redefining tone frequencies),
6. pitch pipe,
and many more.
If you were looking for a guitar tuner, try it!
(*) the INTERNET permission is used for ads only.
(**) most of the historic temperaments were included courtesy of NetCat AG.