n. [ Coal + 2d sack. ] (Astron.) Any one of the spaces in the Milky Way which are very black, owing to the nearly complete absence of stars; esp., the large space near the Southern Cross sometimes called the Black Magellanic Cloud. [ Webster 1913 Suppl. ]

n. [ Russ. kozak', kazak': cf. Turk. kazāk. ] One of a warlike, pastoral people, skillful as horsemen, inhabiting different parts of the Russian empire and furnishing valuable contingents of irregular cavalry to its armies, those of Little Russia and those of the Don forming the principal divisions. [ 1913 Webster ]

. (Mil.) An outpost consisting of four men, forming one of a single line of posts substituted for the more formal line of sentinels and line of pickets. [ Webster 1913 Suppl. ]