wooden horse; rocking horse
vaulting horse; horse used in gymnastics
the horse (ancient torture device that one was forced to straddle with rocks hanging from the feet)
子供が木馬に乗っている。
The child is riding a rocking horse.
おもちゃ屋さんで、娘は新しい木馬を選んだ。
My daughter chose a new wooden horse at the toy store.
公園で子供が楽しそうに木馬で遊んでいる。
The child is happily playing on the rocking horse in the park.