What is "agnate brother"

Brother \Broth"er\ (br[u^][th]"[~e]r), n.; pl. Brothers (br[u^][th]"[~e]rz) or Brethren (br[e^][th]"r[e^]n). See Brethren. [OE. brother, AS. br[=o][eth]or; akin to OS. brothar, D. broeder, OHG. pruodar, G. bruder, Icel. br[=o][eth]ir, Sw. & Dan. broder, Goth. br[=o][thorn]ar, Ir. brathair, W. brawd, pl. brodyr, Lith. brolis, Lett. brahlis, Russ. brat', Pol. & Serv. brat, OSlav. bratr[u^], L. frater, Skr. bhr[=a]t[.r], Zend bratar brother, Gr. fra`thr, fra`twr, a clansman. The common plural is Brothers; in the solemn style, Brethren, OE. pl. brether, bretheren, AS. dative sing. br[=e][eth]er, nom. pl. br[=o][eth]or, br[=o][eth]ru.

1. A male person who has the same father and mother with another person, or who has one of them only. In the latter case he is more definitely called a half brother, or brother of the half blood.

   Note: A brother having the same mother but different fathers is called a uterine brother, and one having the same father but a different mother is called an agnate brother, or in (Law) a consanguine brother. A brother having the same father and mother is called a brother-german or full brother. The same modifying terms are applied to sister or sibling.

   Two of us in the churchyard lie, My sister and my brother.
   --Wordsworth.

2. One related or closely united to another by some common tie or interest, as of rank, profession, membership in a society, toil, suffering, etc.; -- used among judges, clergymen, monks, physicians, lawyers, professors of religion, etc. ``A brother of your order.''
   --Shak.

   We few, we happy few, we band of brothers, For he to-day that sheds his blood with me Shall be my brother.
   --Shak.

3. One who, or that which, resembles another in distinctive qualities or traits of character.

   He also that is slothful in his work is brother to him that is a great waster.
   --Prov. xviii. 9.

   That April morn Of this the very brother.
   --Wordsworth.

   Note: In Scripture, the term brother is applied to a kinsman by blood more remote than a son of the same parents, as in the case of Abraham and Lot, Jacob and Laban. In a more general sense, brother or brethren is used for fellow-man or fellow-men.

   For of whom such massacre Make they but of their brethren, men of men?
   --Milton.

   Brother Jonathan, a humorous designation for the people of the United States collectively. The phrase is said to have originated from Washington's referring to the patriotic Jonathan Trumbull, governor of Connecticut, as ``Brother Jonathan.''

   Blood brother. See under Blood.

sibling \sib"ling\ [sub + -ling.] (s[i^]b"l[i^]ng), n. a brother or a sister.

Note: Siblings have at least one parent in common. Those related only by a common mother are uterine siblings; those related only by a common father are agnate siblings or consanguine siblings (a legal term). A sibling having both parents in common is a sibling-german or a full brother or full sister. These modifying terms are more commonly used for the more specific uterine brother, uterine sister, agnate brother, brother-german, etc.