Catechism of the Catholic Church §2709 — excerpt
What is contemplative prayer? St. Teresa answers: "Contemplative prayer [oracion mental] in my opinion is nothing else than a close sharing between friends; it means taking time frequently to be alone with him who we know loves us."
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: St. Teresa of Jesus, the Book of Her Life, 8, 5 in the Collected Works of St. Teresa of Avila, tr. K. Kavanaugh, OCD, · O. Rodriguez, OCD (Washington DC: Institute of Carmelite Studies, 1976), I, 67