Permalink means Permanent link. " A permalink, or permanent link, is a URL that points to a specific blog or forum entry after it has passed from the front page to the archives. Because a permalink remains unchanged indefinitely, it is less susceptible to link rot. Most modern weblogging and content-syndication software systems support such links. Other types of websites use permanent links, but the term permalink is most common within the blogosphere. Permalink is a portmanteau word made from permanent link. Permalinks are often simply stated so as to be human-readable. " (from wikipedia)
Perma or permanent link means Links that remains life time for your site on directory, articles ditectory, blog and social bookmarkeing. I means these links is one way and remain life time.