The land whence poms (Brits, usually the English) hail; the United Kingdom, or England.
Usually used in the context of Aussies (or occasionally Kiwis or Saffas) expressing national pride, such as in sporting events between Australia and the UK/England, the term is also used when good-naturedly ribbing English people in these peoples' countries.
Pom: <Optimistically> "You know, England might just win the Ashes this year..."
Aussie: "Hahaha, yeah, good one mate, we're sending your boys packing back to Pommyland just like we always do"
Pom: *Sniff*
Pom: "I mean it, why aren't there more clouds in your sky! It's unnatural and my pasty skin can't handle your fucking sun!"
Aussie: "Or perhaps you should just fuck off back to cold old Pommyland you whinging pommy bastard"
<Pair share jovial grin and heartily clink pint glasses>
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