jackhammerjackhammer /ˈdʒækˌhæmɚ/ noun [countable] 
a large powerful tool used to break hard materials such as the surface of a road
a large powerful tool used to break hard materials such as the surface of a road- recognizance
- recognize
- recoil
- recollect
- recollection
- recombinant DNA
- recommend
- recommendation
- recompense
- reconcile
- reconciliation
- recondite
- recondition
- reconditioned
- reconnaissance
- reconnoiter
- reconsider
- reconsideration
- reconstitute
- reconstitution
- reconstruct
- reconstruction
- record
- record-breaking
- recorder