2. (Mil.) pl. Foreign troops in the service of a nation at
war; (rarely in sing.), a member of the allied or
subsidiary force.
3. (Gram.) A verb which helps to form the voices, modes, and
tenses of other verbs; -- called, also, an auxiliary verb;
as, have, be, may, can, do, must, shall, and will, in
English; [^e]tre and avoir, in French; avere and essere,
in Italian; estar and haber, in Spanish.
4. (Math.) A quantity introduced for the purpose of
simplifying or facilitating some operation, as in
equations or trigonometrical formul[ae]. --Math. Dict.