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

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

Children who carried epigenetic patterns associated with ASD were less likely to show signs of the condition if they acquired Lachnospira pectinoschiza during infancy.

From Science Daily • Jun. 2, 2026

Ruck adds that there were "a few other tourists knocking about for a summer family holiday kind of thing", but that it "definitely felt like it was in its infancy".

From BBC • May 24, 2026

But much of the technology is still in its infancy, and there’s still time to get it right.

From The Wall Street Journal • May 2, 2026

He also had his duties as district mathematician, and he soon remarried, a young woman of 24 who bore him six children, three of whom died in infancy.

From "The Scientists" by John Gribbin

Related Words

• inception