Soname

In Unix and Unix-like operating systems, a soname is a field of data in a shared object file. The soname is a string, which is used as a "logical name" describing the functionality of the object. Typically, that name is equal to the filename of the library, or to a prefix thereof, e.g. codice_1.
Name.
The soname is often used to provide version backwards-compatibility information. For instance, if versions 1.0 through 1.9 of the shared library codice_2 provide identical interfaces, they would all have the same soname, e.g. codice_3. If the system only includes version 1.3 of that shared object, with filename codice_4, the soname field of the shared object tells the system that it can be used to fill the dependency for a binary which was originally compiled using version 1.2.
If the application binary interface (ABI) of a library changes in a backward-incompatible way, the soname would be incremented, e.g. from codice_5 to codice_6.
The GNU linker uses the codice_7 or codice_8 to specify the library name field. Internally, the linker will create a codice_9 field and populate it with codice_10.
Given any shared object file, one can use the following command to get the information from within the library file using objdump:
$ objdump -p libx.so.1.3 | grep SONAME
 SONAME libx.so.1