infancy

American  

[in-fuhn-see] / ˈɪn fən si /

noun

infancies plural

1. the state or period of being an infant; very early childhood, usually the period before being able to walk; babyhood.

2. the corresponding period in the existence of anything; very early stage.

   Space science is in its infancy.

3. infants collectively.

4. Law. the period of life to the age of majority, 21 years at common law but now usually 18; minority; nonage.

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infancy British  

/ ˈɪnfənsɪ /

noun

1. the state or period of being an infant; childhood

2. an early stage of growth or development

3. infants collectively

4. the period of life prior to attaining legal majority (reached at 21 under common law, at 18 by statute); minority nonage

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Other Word Forms

Noun Inflected Forms

• infancies
  plural

Etymology

Origin of infancy

From the Latin word infantia, dating back to 1485–95. See infant, -cy

Explanation

Infancy is the earliest part of a person's life, when they're a baby. It's extremely rare for anyone to remember their own infancy. An amazing amount of growth and development happens during infancy: babies learn to crawl, laugh, and communicate, among many other things. Infancy is vaguely defined, usually including the time from birth to about one year old. You can also use the word to mean "the very beginning of something," so if your lemonade stand is brand new, it's still in its infancy. The word comes from the Latin infantia, "early childhood," and literally, "inability to speak."

Example Sentences

But research on teen social-media usage is still in its infancy.

From Barron's • Jun. 15, 2026

Shotwell joined SpaceX in its infancy, at a time when the space industry as a whole was somewhat risky, and a startup even more so.

From MarketWatch • Jun. 11, 2026

The findings, published in Cell Press Blue, suggest that epigenetic changes present at birth can influence how gut bacteria develop during infancy.

From Science Daily • Jun. 2, 2026

Reform was in its infancy the last time these councils in England were up for election, and when the national contests in Scotland and Wales took place.

From BBC • May 8, 2026

Often in one’s infancy, one answers unwittingly to dozens of pet names, until one eventually sticks.

From "The Namesake" by Jhumpa Lahiri

Related Words

• inception