Learn Finnish: Tämä on bussi neljä.

Just like in English, when a number is used as a name or identifier (like a bus route, a room number, or a page), it comes after the noun. Both words stay in their basic, dictionary form.

What happens if I put the number before the noun, like neljä bussi?

If the number comes first, it means you are counting the buses. In Finnish, when you count things (more than one), the noun after the number must change to a special form called the partitive. So, four buses would be neljä bussia. Since we are just naming the bus route here, we do not use that rule.

Is bussi a borrowed word?

Yes, it is a loanword borrowed from languages like English or Swedish. You will also often see the official Finnish word linja-auto (literally line car) on timetables and signs, but bussi is very common in everyday speech.

Why use tämä instead of se here?

tämä means this, pointing to something physically close to the speaker, like a bus you are standing right in front of. If the bus was further away, you would use tuo (that). se usually translates to it, which is used when referring back to a thing you are already talking about.