Nicker/ˈnɪkər/ Definition 1 of 3Pro Tip 1/2Equestrian Context Used to describe sounds that horses make, especially when they're happy or content. At feeding time, the stable was full of quiet nickers. Pro Tip 2/2Animal Communication Conveys a horse's friendly or inquisitive attitude, unlike louder sounds which might indicate alarm. The mare nickered, inviting the foal to her side.