Meaning and local context
In Chicago, “two three tree” means A stylised way of representing Chicago-area pronunciation of numbers and th sounds. More accent commentary than a word people formally write.
Example in context
A local example is “Meet me at two, three, tree.” In plain English, that means “Meet me at two, three, three.”
Meet me at two, three, tree.
Meet me at two, three, three.
How to interpret it
The surrounding sentence is important when interpreting “two three tree”. Use the regional sense above when the situation matches the example instead of relying on the word or phrase in isolation.
Tone and caution
Avoid caricaturing a Chicago accent. Because this is informal regional language, tone and situation should guide whether you use “two three tree” yourself or simply recognise it when someone else uses it.