Definition of start on
1 : to begin doing (something) Did you start on your homework yet?
2 : to cause (someone) to start doing or using (something) The doctor started him on a treatment with antibiotics. When should we start the baby on solid food?
Word by Word Definitions
: to move suddenly and violently : spring
: to react with a sudden brief involuntary movement
: to issue with sudden force
: a sudden involuntary bodily movement or reaction
: a brief and sudden action or movement
: a sudden capricious impulse or outburst
Seen and Heard
What made you want to look up start on? Please tell us where you read or heard it (including the quote, if possible).