A single arrow indicates protection and defense from anything or anyone wishing to harm you in any way. Also, as arrows signify movement or direction of travel, for a wearer it can mean that he/she should keep aiming ahead with force and power, and not look back.
Saudade was once described as "the love that remains" after someone is gone. Saudade is the recollection of feelings, experiences, places or events that once brought excitement, pleasure, well-being, which now triggers the senses and makes one live again. I dig this a lot.