Learn Russian: Ребёнка укачивает в автобусе.

In Russian, experiencing motion sickness is expressed impersonally. The verb укачивать is used in the third-person singular, and the person experiencing the sickness acts as the direct object, so they take the accusative case. The sentence literally translates to 'It makes the child motion-sick in the bus.'

What is the literal meaning of the verb укачивает?

The root of укачивает is related to качать (to rock or swing). Combined with the prefix у-, it means 'to rock to sleep' or, in this context, 'to rock until sick.' It creates the image of the vehicle physically rocking the passenger until they feel nauseous.

How would I say 'I get motion-sick' using this exact structure?

Because the person experiencing the sickness must be in the accusative case, you would use меня (me) instead of the nominative 'I'. The phrase becomes Меня укачивает в автобусе.

Does this verb only apply to road vehicles, or can I use it for seasickness too?

You can use it for any vehicle! The verb укачивать is the standard way to talk about all types of motion sickness. You simply change the location to match the situation, such as в машине (in a car), в самолёте (on a plane), or на корабле (on a ship).