The term “On board” is used a lot in spoken English. Just ask ANY native speaker and they will agree. It’s a great phrase to add to your vocabulary.
If you are “on board” with an idea, it means that you agree with it. Here are some real examples of very native sentences:
1. I think I can convince those 3 girls to join us at the bar tonight. 2 of them are already on board and it’s just the one girl who hasn’t decided yet. I’m sure her friends will get her to go.
2. My boss is totally on board with my new idea for our advertising plan, but his boss disagrees. It will be interesting to see what ends up happening in the end. I’m sure those 2 will have a serious meeting about it.
I hope you enjoyed that lesson! I am sure it will be helpful for you. In today's world, it's important to sound great when you speak English with native speakers. Click on the link for an amazing program to Learn a REAL American Accent


