Why is the ninth month called September?
c.1600, from Latin auxiliaris "helpful," from auxilium "aid, help, support," related to auctus, past participle of augere "to increase" (see augment).
"foreign troops in service of a nation at war," c.1600, from auxiliary (adj.). Related: Auxiliaries.
auxiliary aux·il·ia·ry (ôg-zĭl'yə-rē, -zĭl'ə-rē)adj.
Functioning in an augmenting capacity; supplementary.
Functioning as a subordinate; secondary.