b. Of officials, etc.: That ranks before others by virtue of longer service; senior. Obsolete.
( Elder Brethren: see brothern. 6b.)
ΚΠ
1721–1800 N. BaileyUniversal Etymol. Eng. Dict.Elder Battalion, that Battalion which was first raised, and has the post of honour according to its standing. Elder Officers, such officers whose Commissions bear the eldest Date.