Grammar
N보다
Meaning
BeginnerN boda
보다 is a particle that attaches to a noun and marks that noun as the standard of comparison — 'than N', 'compared with N'. The thing you are comparing against comes before 보다, and the thing you are describing is the subject: 오늘이 어제보다 덥습니다 means 'today is hotter than yesterday'. Adverbs such as 더 ('more') or 훨씬 ('much, by far') are often added after the 보다 phrase to say how big the gap is.
Form
보다 attaches straight onto a noun with no change for a final consonant: 어제보다, 작년보다, 버스보다. It is a particle, not a verb ending, so it is written attached to the noun with no space — writing it as -보다 with a hyphen, as though it followed a verb stem, is misleading. Any degree adverb goes after the 보다 phrase and before the predicate: 어제보다 더 덥다 ('hotter than yesterday'), 버스보다 훨씬 빠르다 ('much faster than the bus'). Both 더 and 훨씬 are optional, since 어제보다 춥다 is already a complete comparison.
Examples
오늘은 어제보다 춥습니다.
Today is colder than yesterday.
오늘이 어제보다 더 덥습니다.
Today is hotter than yesterday.
버스보다 지하철이 훨씬 빠릅니다.
The subway is much faster than the bus.
오늘 날씨는 어제보다 많이 춥습니다.
Today's weather is much colder than yesterday's.
가격이 작년보다 많이 올랐습니다.
The price has gone up a lot compared to last year.
Common mistakes & nuance
The most common mistake is putting 보다 on the wrong noun. 오늘이 어제보다 덥습니다 says today is the hotter one; 어제가 오늘보다 덥습니다 says the opposite. Korean also has a separate adverb 보다 meaning 'more', used before an adjective in written style (보다 나은 결과, 'a better result') — that one is its own word and takes a space after it, so do not confuse it with the particle.
Similar grammar
- N과/와 비교하면
N보다 builds the comparison into the sentence by marking the yardstick noun directly. N과/와 비교하면 sets the yardstick up as a separate opening phrase ('compared with N, ...'), which is why news writing prefers it when two sets of figures are being weighed against each other.