Perambulator
/pəˈræmbjuleɪtər/
Definition 1 of 3
Pro Tip 1/3British Origin
The term is more common in British English than American, where 'stroller' is used. 
In the UK, you'll often hear parents refer to their stroller as a perambulator.
Pro Tip 2/3Old-Fashioned Tone
Using 'perambulator' can give a quaint, old-fashioned feel to your language. 
The old photograph showed a woman with a large-wheeled perambulator.
Pro Tip 3/3Formal Context
'Perambulator' may sound overly formal; 'pram' or 'buggy' is more casual. 
For a walk in the park, simply take the pram instead of saying 'perambulator.'