ENGLISH COMPOUND WORDS 1

Grammar review English compound words are notoriously unpredictable: some are written as one word (bedroom), some are hyphenated (well-known), and some stay as two separate words (ice cream). There's no single rule that covers all of them, but a few patterns cover most cases.

Before a noun, it's usually hyphenated: when a compound adjective comes right before the noun it's describing, it's often joined with a hyphen: a well-known author, a full-length movie, high-quality materials.

After a noun, the hyphen usually disappears: The author is well known., The movie was full length.

Adverb + adjective usually has no hyphen when the adverb ends in -ly: a highly rated show, a poorly written article. The -ly ending already makes it clear the adverb is modifying the adjective, so the hyphen isn't needed.

Noun + adjective is often hyphenated: snow-white fur, oil-rich country.

Familiar compounds can fuse into one word over time. Nationwide and online both used to be hyphenated. There's no hard rule here, just common usage, so a good dictionary is your best backup when you're not sure.