Why were these groups called monasteries and how did they choose their members

The name probably originates from the name for the members, monks, who were male members of strict religious orders. Generally, one became a monk though one's family making arrangements, and often fathers would volunteer their children from a young age. Young women were also registered as nuns in abbeys, the equivalent of a monastery for a woman.

Monasteries were based on groups of men who are monks and who centers their lives on religion. One becomes a monk generally through their neighborhoods for material support