How to write the names of complex terms in the code?

Question

Java

Good afternoon.
For example, I am implementing a cash register. There are the terms "Calculation Sign", "Income", "Expense", ... Of course, this is translated into English, but firstly, I cannot check whether I translated it correctly, and secondly, when there are a lot of terms, then I forget what they mean. Question how to be? How to be right?
1. Write in Russian letters. Clearly. Then you'll get tired of switching the layout and it's still unknown how it will be reflected in postgres.
2. Write in transliteration: priznakRascheta. While the closest option, but something in the soul resists.
3. Translate into English.
4. Your option?

Answer 1

3. Translate into English.

true

Answer 2

You can write javaDoc in Russian / two languages.