ㄴ

Squeezed-together topic marker

This is the ordinary topic marker 은/는 crushed onto the end of the previous syllable in fast speech and casual writing: "that thing is", "this time", "in this situation", all collapsing into one syllable each. It means exactly what the full topic marker means — it sets up what the sentence is about, usually with a hint of contrast against something else. Learners miss it because there is no separate word left to see; the ㄴ is simply riding on the end of a word.

Register: spoken and casual writing