Breakthrough vs. Break Through
“Breakthrough” is a closed noun for an important discovery or advance and can also modify a following noun. “Break through” is the two-word phrasal verb for forcing or moving through a barrier or threshold.
Use “breakthrough” for the noun or attributive adjective and “break through” for the phrasal verb.
Key details
Choose the right form
| If you mean / need | Use | Why |
|---|---|---|
| an important discovery, advance, or attributive modifier | breakthrough | The noun/adjective is written as one word. |
| the action of forcing or moving through something | break through | The phrasal verb is written as two words. |
Further guidance
Core difference
Use the noun or modifier form documented by the dictionaries when naming a thing, event, result, or concept; use the spaced form when the words function as a verb.
Fast Test
If the expression can take ordinary verb tense or inflection in the sentence, the spaced phrasal-verb form is usually the relevant form.
Variant Boundary
Cambridge documents the closed noun/adjective “breakthrough” separately from the two-word phrasal verb “break through.”
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- BREAKTHROUGH — English meaning (opens in a new tab)Cambridge Dictionary · Closed noun/adjective “breakthrough” for an important advance
- BREAK THROUGH SOMETHING — English meaning (opens in a new tab)Cambridge Dictionary · Two-word phrasal verb “break through”