A tentacle or bothrium (plural: bothria) is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like other muscular hydrostats. The word tentillum is a diminutive, but although it literally means "a little tentacle", it usually refers, irrespective of size, to a side branch of a larger tentacle. In some cases such tentilla are specialised for particular functions; for example, in the Cnidaria tentilla usually bear cnidocytes, whereas in the Ctenophora they usually bear collocytes.

The phylum Mollusca includes many species with muscular hydrostats in the form of tentacles and arms. Octopuses do not have tentacles but rather have eight arms. Tentacles are distinguished in this context as being longer than arms, with suckers at their tips only. Squid and cuttlefish have eight arms like octopuses, and two extra flexible tentacles.

The Japanese people (日本人, Nihonjin, Nipponjin^?) are a nationality originating in the Japanese archipelago and are the predominant ethnic group of Japan. Worldwide, approximately 130 million people are of Japanese descent; of these, approximately 127 million are residents of Japan. People of Japanese ancestry who live in other countries are referred to as nikkeijin (日系人^?). The term ethnic Japanese may also be used in some contexts to refer to a locus of ethnic groups including the Yamato, Ainu and Ryukyuan people.

The Japanese language is a Japonic language that is sometimes treated as a language isolate; it is also related to the Ryukyuan languages, and both are suggested to be part of the proposed Altaic language family. The Japanese language has a tripartite writing system using Hiragana, Katakana, and Kanji. Domestic Japanese people use primarily Japanese for daily interaction. The adult literacy rate in Japan exceeds 99%.

Japanese religion has traditionally been syncretic in nature, combining elements of Buddhism and Shinto. Shinto, a polytheistic religion with no book of religious canon, is Japan's native religion. Shinto was one of the traditional grounds for the right to the throne of the Japanese imperial family, and was codified as the state religion in 1868 (State Shinto was abolished by the American occupation in 1945). Mahayana Buddhism came to Japan in the sixth century and evolved into many different sects. Today the largest form of Buddhism among Japanese people is the Jōdo Shinshū sect founded by Shinran.^{[citation needed]}