From a 1991 Catholic Update by Thomas Richstatter, O.F.M., S.T.D., titled "A Tour of a Catholic Church":
Also in this baptismal area of the narthex or vestibule of the church, you will see a niche in the wall or a little chest, the ambry, which contains three vessels of oil: the oil of catechumens which is used to bless and strengthen those preparing for baptism; the oil of the sick with which the priest brings Jesus' strength and healing to those who are joined with the suffering Christ in serious illness; and the sacred chrism which is used in celebrating the sacraments of Baptism, Confirmation, and Holy Orders.
According to the OED, the phonetic development went like so: armarium, almarium, almary, almery, aumery, aumry, aumbry.
Outside of a church setting, an ambry is defined (in the OED) as "A repository or place for keeping things; a storehouse, a treasury; a cupboard (either in the recess of a wall or as a separate article of furniture); a safe; a locker, a press."
If "Cristabel" could provide an appropriate citation, it might look like:
Her gentle hair she soaked with tea
Kept safe and dry in the oak ambry.
Unfortunately, Coleridge penned otherwise:
Her gentle limbs did she undress
And lay down in her loveliness.
The next Update in the series, by the way, was to be titled "Catholic-Jewish Relations: 'We've Come a Long Way!'"