The term 'young ___ (children)' can be filled in with two words: UNS and TOTS. UNS is a three-letter word meaning 'young children' and is derived from the Old English word 'unscea, ' which means 'infant.' TOTS is a four-letter word meaning 'very young children' and is derived from the Middle English word 'toten, ' which means 'to teach.' Both words are used to refer to young children, but UNS is more commonly used to refer to infants, while TOTS is more commonly used to refer to toddlers.