Infancy is the earliest stage of life, typically covering a baby's first year or two. During infancy, humans grow and develop faster than at any other time in their lives. An infant (another word for baby) learns to recognize faces, smile, roll over, sit up, crawl, and often take their first steps, all within just the first year.

Infants communicate through crying, cooing, and gestures until language develops.

Scientists and doctors pay close attention to infancy because so much crucial development happens during this period. An infant's brain forms millions of new connections every day as they experience the world for the first time.

The word also describes the very beginning of anything new. When the internet was in its infancy during the 1970s and 80s, only universities and researchers used it. When someone says a technology or idea is still in its infancy, they mean it's just getting started and has a long way to go before reaching its full potential.