The Claddagh's distinctive design features two hands clasping a heart, and usually surmounted by a crown. The elements of this symbol are often said to correspond to the qualities of love (the heart), friendship (the hands), and loyalty (the crown).
The way that a Claddagh ring is worn on the hand is usually intended to convey the wearer's romantic availability, or lack thereof.
Traditionally, if the ring is on the right hand with the heart facing outward and away from the body, this indicates that the person wearing the ring is not in any serious relationship, and may in fact be single and looking for a relationship: "their heart is open."
When worn on the right hand but with the heart facing inward toward the body, this indicates the person wearing the ring is in a relationship, or that "someone has captured their heart".
A Claddagh worn on the left hand ring finger facing outward away from the body generally indicates that the wearer is engaged.
When the ring is on the left hand ring finger and facing inward toward the body, it generally means that the person wearing the ring is married.