The word "婴幼儿" is formed by combining three distinct characters: "婴" meaning infant, "幼" meaning young, and "儿" meaning child. Each character contributes its specific semantic value to create a composite term that refers to the collective stage of early childhood, from infancy to young children. The order progresses from younger to slightly older, with "婴" denoting newborns, "幼" indicating toddler years, and "儿" encompassing childhood broadly, resulting in a precise lexical unit for this age group.