Bonding Anima

A Bond is the link you form with a Nexus Anima that lets you summon and use it. In most cases you create the Bond after defeating that Anima in battle. While exploring, any Anima you haven't bonded yet is marked with a special icon floating above it, so the ones still available are easy to spot.

Confidence: unconfirmed · Source: the in-game Handbook (via the Fandom wiki). Pre-release; may change.