Foreign Word
Borrowed Word, Loanword
You know the word 外来 to mean "imported." So, combine that with the kanji for language and you have an imported word, aka a borrowed word. There are a lot of these in Japanese, which makes this word important. Almost everything in katakana is a 外来語, in fact.
がいらいご
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
げんざいの中国語では、たくさんの日本語が外来語として使われています。
Many Japanese words are used as loanwords in modern day Chinese.
リュックサックは、外来語ですか？それとも和せいえい語ですか？
Is rucksack a foreign word, or Engrish?
ねえ、煙草って外来語なのに漢字があるって知ってた？
Hey, did you know that there's kanji for the word tobacco even though it’s a loanword?