I searched for the meaning of “as” in English-Spanish Oxford dictionary, which says it is used to define a word. Is this true?
(defining):
① it would be the end of civilization as we know it
significaría el fin de la civilización tal y como la conocemos
② I'm only interested in the changes as they affect me
solo me interesan los cambios en la medida en que me afectan a mí
③ Sri Lanka, or Ceylon, as it used to be known
Sri Lanka, o Ceilán, como se llamaba antes
④ Paris as seen by tourists is a very different city
el París que ven los turistas es una ciudad muy distinta
⑤ their position, as opposed to ours
su postura, en contraste con la nuestra