- join in and help with something
- join forces with others
- contribute something towards a common endeavour
- do something helpful as part of a group
- On Jane’s birthday her friends decided to pitch in and have a surprise party for her.
- As his medical expenses kept soaring, his entire family pitched in so that he could carry on his treatment.
- Last weekend we all pitched in and started mowing the field.
- During our camping trip, everyone pitched in and set up the tent.
- We are having a farewell party for him tonight, would you like to pitch in?
- It was a difficult task, but when everyone pitched in, it was finished quite fast.
- Why don’t you pitch in and help us with the arrangements?
- Let’s pitch in with the team and go for a hike together.
The origin of this phrase is not known.