In modern usage, a community of *secular clergy, with extensive parochial rights; these were being eroded from the 10c by the foundation of single-priest churches on individual manors, the latter forming the basis for the later system of parishes. Consequently, many minsters disappeared, though their former presence can be detected in place names ending in‘-minster’, e.g. Charminster and Beaminster. Before 1066, the word was used both of secular and monastic communities, but always with the sense of a superior church. [OE mynster < monasterium = monastery]
*Source: A Dictionary of Medieval Terms & Phrases by Christopher Coredon with Ann Williams
From the The Anglo-Saxon Dooms, 560-975:
Let the aldor of a minster clear himself with a priest’s canne…
If any one carry off a nun from a minster, without the king’s or the bishop’s leave, let him pay a hundred and twenty shillings, half to the king, half to the bishop and to the church-hlaford who owns the nun. If she live longer than he who carried her off, let her not have aught of his property. If she bear a child, let not that have of the property more than the mother. If any one slay her child, let him pay to the king the maternal kindred’s share; to the paternal kindred let their share be given. . . .