Source : Free On-Line Dictionary of Computing

inode
     
        A data structure holding information about files in a {Unix}
        {file system}.  There is an inode for each file and a file
        is uniquely identified by the file system on which it
        resides and its inode number on that system.  Each inode
        contains the following information: the device where the inode
        resides, locking information, mode and type of file, the
        number of links to the file, the owner's user and group ids,
        the number of bytes in the file, access and modification
        times, the time the inode itself was last modified and the
        addresses of the file's blocks on disk.  A {Unix} directory is
        an association between file leafnames and inode numbers.  A
        file's inode number can be found using the "-i" switch to ls.
     
        {Unix manual page}: fs(5).
     
        See also /usr/include/ufs/inode.h.