[1850–55; ex-1 + territorial]This word is first recorded in the period 1850–55. Other words that entered Englishat around the same time include: headhunting, muggins, overprint, proletariat, runoffex- is a prefix meaning “out of,” “from,” and hence “utterly,” “thoroughly,” and sometimesimparting a privative or negative force or indicating a former title, status, etc.;freely used as an English formative. Other words that use the affix ex- include: ex-member, ex-wife, exstipulate