what's the original form of this word?

[MAHaifeng]

I am trying to translate Cato's "de Agri Cultura", but one sentence got me, I refered to the Latin-English dictionary again and again to understand the meaning of the word "siet", but what depressed me was that I couldn't find this word, is anybody here who can help me? I will really appreciate your help.Thanks.

[Gonzalo]

It's the manner in which Cato uses sit (third person, singular, present of subjunctive mode of esse, to be), as far as I can understand. I have read an excerpt or selection published by Hans Orberg in a book entitled Sermones Romani (which includes I,2 from De Agri Cultura) and there's a note which states:
siet, sient=sit, sint

Regards

[adrianus]

This is just to confirm what Gonzalo is saying for the present subjunctive of esse, from the note in Allen and Greenough, New Latin Grammar, section 170, b of the old forms siem sies siet simus sitis sient for sim sis etc as Gonzalo says. Just another source to look up.