Heaven's Lost Property - Terminology

Terminology

Synapse (シナプス, Shinapusu?)

Synapse is a land located in the skies that is home to the Angels and the Angeloids. It was first introduced in the series as a black hole above Sorami. Sugata believes that Synapse is the "New World" and begins to investigate it. After discovering that Nymph's Dive Game is capable of providing a portal between Sorami and Synapse, Sugata asks Nymph to help him. In Synapse, there is a large dome that contains numerous Angels in sleeping pods, which connects them to their real-world avatars. If the avatar in the real world is killed, the people associated with them will have their memories erased, such as the case with Hiyori. Also in Synapse is a large obelisk called the Core, which has its rules written on it.

Angeloids (エンジェロイド, Enjeroido?)

The Angeloids are a series of gynoids built by Synapse. As part of their name implies, they are modeled after the Angels and are programmed to serve their masters. The Angeloid selects her master through a process called "Imprinting", in which the chain attached to her neck collar extends to her chosen master's hand. The first generation of Angeloids (Ikaros, Nymph, and Astraea) were built by Daedalus, while the second generation of Angeloids (Chaos, Hiyori, Seiren, and Ikaros Melan) have been built (or in Hiyori's case, converted to) by the Master of Synapse.

Each Angeloid is designated with a letter of the Greek alphabet, which descends for every new Angeloid built. Ikaros, the first Angeloid built, is a "Type Alpha" Angeloid, while Ikaros Melan, the most recent Angeloid, is a "Type Theta" Angeloid. Each Angeloid has their own unique abilities and powers, which are determined from three main parameters: battle capability, emotional control and processing capability. Unlike humans and Angels, Angeloids cannot sleep or have dreams, except for Chaos. The Angeloids are able to perform other human functions such as eating and expressing emotions. With the execption of Seiren (and consequently Chaos), Angeloids cannot swim because their wings absorb water, which causes them to sink, however, Ikaros is able to function underwater. The Angeloids' names, weapons, and abilities are primarily derived from Greek gods and mythological figures.

Self-Evolution Program Pandora (自己進化プログラムパンドラ, Jiko Shinka Puroguramu Pandora?)

A program built into certain Angeloids that allow them to learn and adapt to various environments and situations and eventually evolve into stronger beings with additional capabilities. Chaos is the first to demonstrate its ability when she absorbs Second-Generation Angeloid Seiren and grows amphibian wings to swim underwater. Daedalus later reveals that she built the Pandora program into her First-Generation Angeloids but added a protection layer so they would not evolve "by mistake". In chapter 55, Nymph is the first one to break the protection layer and evolve her Aprodite mode, and the end of the chapter, a severely damaged Ikaros, previously assumed irrepairable with 97% of her systems damaged and her self-repair program destroyed, also activates Pandora to evolve.