There are 17 words that start with 'robo'.
| robot | robots | 
| robotic | robotry | 
| roborant | robotics | 
| robotism | robotize | 
| roborants | robotisms | 
| robotized | robotizes | 
| robotries | robotizing | 
| robotically | robotization | 
| robotizations | |
Note: These 17 words that start with 'robo' are found from the USA & Canada version of the tournament Scrabble word list.