/ frəˈtɜːnl; NAmE -ˈtɜːrnl/ adjective [ usually before noun ]
1.
connected with the relationship that exists between people or groups that share the same ideas or interests :
a fraternal organization / society
2.
connected with the relationship that exists between brothers :
fraternal rivalry
► fra·ter·nal·ly adverb
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WORD ORIGIN
late Middle English : from medieval Latin fraternalis , from Latin fraternus , from frater brother.