From the Latin: therefore.
In English ergo is mostly used, if
at all, in Latin phrases, as 'cogito ergo sum'. But whether 'ergo' or
'therefore' is used, it is important to realize that who uses it desires to
indicate that what came before the 'ergo' or 'therefore' serves as a
premiss or premisses, and what follows
it is a
conclusion. Also, the user suggests by using 'ergo' and 'therefore'
that the premiss(es) entails the conclusion in a logically
valid way, but this may be a mistake even if
the suggestion is sincere.