Catechism of the Catholic Church §930 — excerpt
Alongside the different forms of consecrated life are "societies of apostolic life whose members without religious vows pursue the particular apostolic purpose of their society, and lead a life as brothers or sisters in common according to a particular manner of life, strive for the perfection of charity through the observance of the constitutions.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: CIC, can. 731 ## 1 · 2