Continuous Integration (CI)
is a development practice, in software engineering, of merging all developer working copies to a shared mainline serveral times a day
Continuous Delivery (CD)
is a software engineering approach in which teams produce software in short cycles, ensuring that the software can be reliably released at any time.
is about sharing a collaborative culture, sharing automation and tools, and sharing common measurements. In this sense, sharing is the feedback mechanism that helps teams learn from the own efforts, and from the efforts of others.