‘婴幼’ is a compound noun meaning ‘infancy and early childhood’, typically referring to the developmental stage from birth up to around age six. The character 婴 (yīng) means ‘infant’ or ‘baby’, often evoking newborns or very young children, while 幼 (yòu) means ‘young’, ‘juvenile’, or ‘immature’, extending the scope to toddlers and preschoolers. Together, they form a formal, concise term used especially in professional, medical, educational, or policy contexts — such as healthcare guidelines, parenting resources, or government regulations.

This word rarely appears alone in casual speech; it’s almost always part of longer compounds like 婴幼儿 (yīng yòu ér, ‘infants and young children’) or 婴幼保健 (yīng yòu bǎo jiàn, ‘infant and early childhood health care’). It carries a neutral, objective tone and emphasizes developmental vulnerability and care needs during this critical life stage.