regulaarsõ
Regulaarsõ is a term that appears to be a misspelling or a non-standard word in Estonian. The word "regulaarne" in Estonian means "regular." The suffix "-sõ" does not form a common or recognized grammatical or lexical element in the Estonian language. It is possible that the user intended to type a different word, or "regulaarsõ" is a very specific neologism or dialectal term that is not widely documented.
If the intended word was "regulaarselt," this would be the adverbial form of "regulaarne," meaning "regularly."
Alternatively, "regulaarsõ" could be a typographical error for a word with a similar sound. Without further