A small storehouse and...
Monastery is one of those Terms that is commonly misinterpreted to mean a building containing several Monks.
Monasteries vary greatly in size, comprising a small dwelling accommodating only a hermit, or in the case of communities anything from a single building housing only one senior and two or three junior monks or nuns, to vast complexes and estates housing tens or hundreds.
Not every Monastery had a church, either inside, attached or seperate to the building..a lot only had (and still have) a chapel, a room set aside for prayer/Meditation and could be used as an oratory, ie; it could be used in the way a classic church would be with a Speaker talking to the congregation.
A monastery generally includes a place reserved for prayer which may be a chapel, church or temple, and may also serve as an oratory.
Generally as in, not always ;-)
Logically, Some monasterys having only a singular Monk, would make having a Chapel, let alone a church, a bit much to ask of the poor lonely celibate. This all of course depends on the Interpretation of what constitutes a "church"
In the case of my "monastery" it could theoretically be that the place of contemplation/prayer is inside the main building in a crypt for example or entirely seperate from the main building and not in view..and that´s if I was to use it as a Monastery.