sibling (n.)

• agnate
• akin
• ancestry
• blood
• clansman
• cognate
• collateral
• congeneric
• enate
• family
• flesh
• folks
• foster
• german
• kin
• kindred
• kinfolk
• kinsfolk
• kinsman
• kinswoman
• people
• posterity
• relations
• sib
• tribesman