262. In accordance with Christian revelation, the risen Christ is the supreme and definitive sanctuary (cf. John 2, 18-21; Rev 21, 22) around which the community of the disciples gathers. In turn, that community is the new dwelling place of the Lord (cf. 1 Pt 2, 5; Eph 2, 19-22).
A useful definition for our consideration:
Theologically, a shrine, which often derives from popular piety, is a sign of the active and saving presence of the Lord in history, and a place of respite in which the people of God on its journey to the heavenly City (cf. Heb 13, 14), can renew its strength for the pilgrim journey (Cf. Pontifical Council for the Pastoral Care of Migrants and Itinerants, The Shrine. memory, presence and prophecy of the living God. (8.5.1999), Libreria Editrice Vaticana, Città del Vaticano 1999).
The Directory on Popular Piety and the Liturgy is online at the Vatican site.