Short answers, pulled from the story.
The word chibi originates from a Japanese colloquialism meaning very short people or children. It derives from the Japanese word chibi meaning small or tiny, with the suffix i added as a loanword from the English word character to create a compound that literally translates to small character.
Chibi characters compress the body so that the head occupies anywhere from one third to one half of the total height. Unlike standard anime figures which typically stand seven to eight heads tall, chibi figures feature stubby, chubby bodies with oversized eyes and tiny noses.
The chibi style gained international prominence by the mid-1990s when the character Chibiusa appeared in manga works and merchandise. This specific example from the mid-1990s marked a turning point where the style transitioned from a niche manga technique to a recognizable element of anime culture.
Anime-influenced American series such as Teen Titans, Avatar: The Last Airbender, and Homestuck adopted the chibi style. These productions used the exaggerated proportions to inject humor, relieve tension, or emphasize the innocence of certain characters within their respective narratives.
The chibi style triggers a psychological response known as baby schema by mimicking the features of human infants. This biological response causes the brain to release dopamine and oxytocin, evoking feelings of protectiveness and affection in the viewer.