"Therefore . . ." - Crossword Clue, Answer and Explanation

'therefore' is the definition.
(I know that therefore can be written as thus)

This is all the clue.

(Other definitions for thus that I've seen before include "In this way" , "as indicated" , "an original Christmas gift" , "It follows" , "Therefore, hence" .)

I've seen this clue in the Universal, The Wall Street Journal, the Evening Standard, the Penny Press, The Telegraph, the Newsday.com, The Guardian, the King Feature Syndicate, the USA Today, the Newsday, The New York Times, the LA Times, The Times, The Washington Post, The Mirror, The Independent, The Sun, the Sydney Morning Herald and The Star Tribune.

'therefore' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for ergo that I've seen before include "Thus" , "Consequently" , "'Cogito, ---- sum'" , "so philosopher wrote in Latin" , "It follows" .)

I've seen this clue in the Universal, The Wall Street Journal, the Evening Standard, the Penny Press, The Telegraph, the Newsday.com, The Guardian, the King Feature Syndicate, the USA Today, the Newsday, The New York Times, the LA Times, The Times, The Washington Post, The Mirror, The Independent, The Sun, the Sydney Morning Herald and The Star Tribune.

'therefore' is the definition.
('so' can mean 'consequently' or 'therefore')

This is all the clue.

I've seen this clue in the King Feature Syndicate.

"Therefore . . ." (5)