The English language has several terms for children between the ages of birth and 4 years, including newborn, infant, baby, and toddler. These words are often used interchangeably, and they may mean different things to different people.
But what age is really considered a newborn? How about a baby, infant, or toddler? Here, we explore each of these terms and their age ranges. We also give an overview of the growth and development you can expect during each timeframe.
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What Age Is an Infant, Baby, and Newborn?
Though the terms "newborn," "baby," and "infant" are frequently used synonymously, the exact definition depends on the source you consult.
The Merriam-Webster dictionary simply says a newborn is an individual who was recently bornand doesn't put an upper limit on the term. Merriam-Webster also defines an infant as "a child in the first period of life,"but doesn't give any age specifics. They describe a baby as "an extremely young child."
The World Health Organization (WHO) defines a newborn infant, or neonate, as a child that's under 28 days old. On the other hand, the Centers for Disease Control and Prevention (CDC) says the infant stages stretches from birth to 1 year old.
Definitions
- Newborn usually refers to a baby from birth to about 2 months of age.
- Children can be considered an infant anywhere from birth to 1 year old.
- Baby can refer to any child from birth to age 4 years old, thus encompassing newborns, infants, and toddlers.
Growth and Development
Between birth to 1 year of age, kids develop at an astounding rate. They'll hit many milestones, which might include the following:
- Rolling over
- Smiling
- Sitting up
- Waving
- Clapping
- Picking up objects
- Crawling
- Babbling
- Possibly saying a few words
Babies generally triple their birth weight and grow around 10 inches during their first year. During this time, they'll also learn to bond with their caregivers, and they understand more than they're able to communicate. Babies enjoy music, movement, and simple games like peek-a-boo.
Areas of Concern
Babies develop at different rates, and it's normal for them to reach milestones at different ages. However, if you are worried about your baby's development, check with your pediatrician.
Your baby's doctor can reassure you or refer you to a specialist if there's a need for further evaluation. Take note if your baby seems to lag in these areas:
- Smiling
- Waving, pointing, reaching, and making other gestures with their hands
- Rolling over, crawling, or sitting up unassisted
- Babbling or otherwise attempting to communicate vocally
- Knowing and responding to their name
What Age Is a Toddler?
A baby is generally considered a toddler beginning around 1 year (12 months) of age. There's no official "upper limit" of toddlerhood, but most people consider the end of the toddler age to be around the time a child transitions into preschool.
Indeed, the CDC says that kids ages 1 to 3 are considered toddlers, while 3- to 5-year-olds are preschoolers. The American Academy of Pediatrics (AAP) follows the same definitions.
Toddler Growth and Development
As kids move into their second year of life, they become more mobile and independent, exploring everything they can access. Here are some milestones you'll notice during the toddler years:
- Walking (usually by 18 months)
- Learning to talk (and eventually speaking in phrases and sentences)
- Identifying and imitating the people around them
- Following simple instructions
- Feeding themselves
- Engaging in play
- Expressing more emotions and awareness
- Imitating the behavior of others
- Running, kicking, and climbing as they near preschool age
Like little sponges, toddlers soak up everything, so memorization comes fairly easily. They still need lots of sleep and may take a nap or two during the day, contributing to a total of 11 to 14 hours of sleep daily. Toddlers enjoy simple games, songs, and rhymes, and they can start learning their colors, shapes, and alphabet.
Areas of Concern
Again, it's completely normal for toddlers to develop at different rates. But check with your pediatrician if your toddler isn't meeting developmental milestones, such as:
- Walking
- Holding lightweight objects
- Chewing and swallowing food
- Adding new words to their vocabulary regularly
- Showing interest in you and other familiar people
- Using two-word phrases (by age two)
