For Linux, the Linux Standard Base describes the filesystem layout and where and how applications and their data are installed.
The LSB references the Filesystem Hierarchy Standard (even though it's terribly out of date) for most items in the filesystem.
As a practical matter, you will find that most applications have their program binaries installed in
/usr/bin, their libraries installed in
/usr/lib64, their shared application data in
/usr/share and their machine-specific application data in
These directories are where the system installs applications.
User-installed applications may be placed under
/usr/local, the conventions for which mirror those for
/usr, or in directories under
/opt which slightly resembles Mac OS X's
/Applications folder, in which each application has a folder directly underneath, and in that folder the directories typically mirror those found under