1.
first cry of a newborn baby
The cry a baby makes immediately after being born. A symbol of new life beginning.
2.
birth, inception, beginning
Used figuratively to describe the start or emergence of an organization, movement, product, or idea.
Usage
Almost always appears in the phrase 産声を上げる, which literally means "to raise one's first cry" and figuratively means "to come into existence" or "to be founded." The figurative use (sense 2) is very common in formal writing about companies, organizations, and movements.
Writing
産 (birth) + 声 (voice/cry). The reading うぶ is a kun'yomi for 産 that specifically means "birth" or "newborn."