The first part of life, beginning at the birth. In common usage, infancy extends not beyond the first year or two of life, but there is not a defined limit where infancy ends, and childhood begins.

In law, infancy extends to the age of twenty one years.

The first age of any thing; the beginning or early period of existence; as the infancy of the Roman republic; the infancy of a college or of a charitable society; the infancy of agriculture, of manufactures, or of commerce.