Air carrier pilot reported a severe turbulence encounter during climb. Flight continued to the destination.

Narrative

On the morning flight from ZZZ to ZZZ1 on Day 0. Moderate Turbulence was reported on initial climb out. We kept the flight attendants seated and briefed the flight crew and made a PA to the passengers about the possible turbulence on the climb. We did not experience anything greater than light turbulence until reaching FL180. Moderate turbulence was encountered and around FL 190 we encountered Severe Turbulence lasting somewhere around 10 seconds. It was hard to judge the time this turbulence was encountered but we exited the Severe conditions around FL 210. Severity of turbulence was determined from description of turbulence from FOM. We lost control of the aircraft momentarily for about 3 seconds ; experiencing a knot loss and gain about 15-20 kts; climbing out at a speed of 290 kts. After exiting conditions no injuries were reported. Aircraft did not encounter any damage that required a diversion. Flight continued to ZZZ1 with no issues. Cause: Turbulence Reported at the departure airport and initial climb. We kept the Flight attendants seated and no injuries were reported. Logbook entry was made and Dispatch was notified of the situation.