Tak in Russian literally means so.
In Cyrillic it’s written так.
Besides meaning so, tak can be used in all sorts of situations with slightly different meanings. For example, it can mean yes if it comes after a question. If it goes in the beginning of the sentence, it means that the person is trying to collect the thoughts and come up with a decision.
Have a look at some examples:
– Всё так? – Да, всё так.
[fsyo tak? – da, fsyo tak]
Is everything alright (so)? – Yes, all is good.
– Так, дава́йте договори́мся о сле́дующем…
[tak, da-váî-tye da-ga-va-réem-sya a slyé-du-yu-schem]
Ok, let’s agree on the following…
– Так не пра́вильно, пра́вильно вот так.
[tak nye prá-veel’-na, prá-veel’-na vot tak]
It’s not correct like that, like that is correct.
Besides, tak often is a part of different expressions with completely different meanings.