Santa Maria in Carinis was an 18th century convent church that used to stand on the north side of the junction between Via del Colosseo and Via del Tempio della Pace, at Via del Colosseo 61a. This is in the rione Monti.
The dedication was to the Nativity of Our Lady.
It was the church of a small Cistercian monastery between 1780 and 1805. This seems to have been a private villa beforehand, as the Nolli map does not show the church but has a large establishment with a garden on the site.
After the monastery was confiscated by the state in 1873, the church was deconsecrated towards the end of the 19th century and the convent replaced by a block of private apartments.
The name Carinis is a mystery. Carina is Latin for a ship's keel, but attempts to connect the two words are guesses at best.
The convent was on the north side of the junction between the Via del Colosseo and the Via di Tempio della Pace. The orientation of the church was east to west along the latter street.
The church was reached through the entrance to the monastery, and its doorway faced this across a small hallway. It was of a simple rectangular plan, with a semi-circular apse containing the only altar.
The lintel of the convent entrance doorway had the name of the church on it. This was preserved in the demolition, and was incorporated into the entrance of the replacement apartment block. Hence it survives.