己 is a pictographic character, resembling a curved rope. 己 mainly serves as a phonetic component to form characters and also serves as a semantic component to express things related to a baby or infant.
Characters formed by the semantic component 己
已 巻 凯 巹
Characters formed by the phonetic component 己
杞 芑 邔 屺 玘 起 岂 have the same pronunciation qǐ
纪 记 忌 梞 跽 have the same pronunciation jì
鱾 妃 配 圮 改 jǐ fēi pèi pǐ gǎi