breakthrough

UK: /ˈbreɪkθruː/ US: /ˈbreɪkˌθru/ ,(brāk′thro̅o̅′)

WordReference Random House Learner's Dictionary of American English © 2025

break•through /ˈbreɪkˌθru/   n. [countable]

1. an important and sudden advance, etc., as in science, that removes a barrier to progress:
   Pasteur's discovery about the nature of germs was an important breakthrough in the treatment of diseases.
2. an act or instance of removing or getting past a barrier:
   The army made its breakthrough at dawn.

WordReference Random House Unabridged Dictionary of American English © 2025

break•through  (brāk′thro̅o̅′), n. 

1. Military a military movement or advance all the way through and beyond an enemy's front-line defense.
2. an act or instance of removing or surpassing an obstruction or restriction;
   the overcoming of a stalemate:
   The president reported a breakthrough in the treaty negotiations.
3. any significant or sudden advance, development, achievement, or increase, as in scientific knowledge or diplomacy, that removes a barrier to progress:
   The jet engine was a major breakthrough in air transport.

adj. 

4. constituting a breakthrough:
   engineered with breakthrough technology; Critics called it a breakthrough film.

• noun, nominal use of verb, verbal phrase break through 1915–20

Collins Concise English Dictionary © HarperCollins Publishers::

break through verb

1. (intransitive) to penetrate
2. (intr, adverb) to achieve success, make a discovery, etc, esp after lengthy efforts

noun breakthrough

1. a significant development or discovery, esp in science
2. the penetration of an enemy's defensive position or line in depth and strength