reintroduction

re- +‎ introduction

reintroduction (plural reintroductions)

1. The act of introducing something again.
2. The release of animals from captivity into the wild, especially, into an area where they have become extirpated or greatly reduced.
   • 2018, Tim Flannery, Europe: A Natural History, page 195:

     The IUCN (International Union for the Conservation of Nature), for example, restricts use of the word ʽreintroductionʼ to species that have become extinct locally or Europe-wide no more than 200 to 300 years ago.

3. (countable) An animal so released.

• nitroreduction