This is the 3022nd most frequent Dutch word.
bootje
A small boat.
In this sentence, 'bootje' is used as a diminutive form of 'boot' to indicate a small boat.
Ik zie een leuk bootje in de haven.
I see a nice little boat in the harbor.
Here, 'bootje' refers to a small boat as a means of transportation along a river.
We gaan met het bootje de rivier op.
We are going up the river with the little boat.
In this example, 'bootje' emphasizes the small size and movement of the boat caused by the waves.