What does the execute permission mean for a directory, a file type for which the execute operation makes no sense?

What will be an ideal response?

The execute permission for a directory allows you to search the directory. Thus you can list the contents of the samples directory by using ls ~/unixbook/scripts/samples if you have the execute permission for the unixbook directory in your home directory and the scripts directory under ~/unixbook, and search and read permissions for samples. If you do not have search permission for a directory, you cannot make that directory your current directory by using the cd command.