When used in sentences, (이)나 can be attached to both subjects and objects to maintain this “or” translation.
However, it is more natural to remove any other particles/grammar points from the first option before (이)나 is added.
Therefore, any particles only appear on the second noun, for example, 엄마나 아빠가 (either my mum or my dad) is used, NOT 엄마가나 아빠가.
*버스나 지하철 (either bus or subway)