AUXILIARY (from Lat. auxilium, help), that which gives aid or support; the term is used in grammar of a verb which completes the tense, mood or voice of another verb; in engineering, e.g. of the low steam power used to supplement the sail-power in sailing ships, still occasionally used in yachts, sealers or whalers; and in military use, of foreign or allied troops, more properly of any troops not permanently maintained under arms. In the British army the term "Auxiliary Forces" was employed formerly to include the Militia, the Imperial Yeomanry and the Volunteers.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)