(trademark) A toy, a small electronic virtual pet.
A portmanteau of the Japanese word tamago and the English word watch (ウオッチ uocchi). Early on, in Japan, Tamagotchi was written in English as Tamagotch. When the Tamagotchi went overseas, an "i" was added at the end or the name. Recently, Japan has changed Tamagotch for Tamagotchi.
English Wiktionary. Available under CC-BY-SA license.