Longman Dictionary of Contemporary English
Wiktionary
a. Of an achievement, exceeding the highest previously recorded level in that activity.
WordNet
adj. surpassing any previously established record; "a record-breaking high jump"; "record-breaking crowds"
Usage examples of "record-breaking".
At the end of their second, record-breaking year of unprecedented sales, brother Kogh Ademian journeyed down to Richmond, hat in hand, visibly eating crow and insisting that it was a familial responsibility for Rupen and Bagrat to keep all the Ademian businesses in the family, not to mention taking advantage of the wealth and influence of his Ademian Enterprises, Incorporated.
Devil's Hand began his breathing exercises and prepared to hoist his sword for the record-breaking attempt, and that was when the first of the extraordinary events that were to entangle us in the affairs of the Eight Skilled Gentlemen occurred.
The record-breaking shot, the effect of it and the struggle that had taken place in the powder room, together with the flight of von Brunderger and his servant, gave many subjects for excited conversation.
Fortunately Emma George's world record-breaking feats in the pole vault kept the spotlight off Freeman's demise.