General:
* Child (most common and neutral)
* Kid (informal, often used for children of any age)
* Little one (affectionate, often used for babies or toddlers)
* Youngster (formal, emphasizes youthfulness)
* Sprout (poetic, emphasizes growth and development)
* Offspring (biological term, emphasizes parentage)
By Age:
* Baby (infant, typically under 1 year old)
* Toddler (child learning to walk, typically 1-3 years old)
* Preschooler (child aged 3-5)
* Schoolchild (child attending school, typically 5-18)
* Teenager (adolescent, typically 13-19)
By Gender:
* Boy
* Girl
Other Specific Nouns:
* Infant (newborn baby)
* Pupil (student in school)
* Ward (child in the care of a guardian)
* Minor (person under the age of legal majority)
Note: Some of these nouns have specific connotations or cultural nuances. For example, "kid" might be considered disrespectful in some contexts, while "little one" is often used affectionately. It's important to choose the appropriate noun based on the specific situation and context.