Infancy
Part of speech: noun
Definition: The earliest period of childhood (crawling rather than walking). The state of being an infant. An early stage in the development of, eg, some technology. The state of being a minor.
Example sentence: Most of my career up until the last couple of years has basically been a training ground for me. Actors that came up in the '50s and '60s, they had the theater, and television was in its infancy.
Babyhood
Part of speech: noun
Definition: The state or period of infancy.