This might help: http://www.genealogyintime.com/dictionaries/list-of-occupation-abbreviations-page-a.html

I was hoping to find something like this but had no luck.

What kind of a document is this? Are these relatives of yours town-dwellers or country folks?

Could they be stave makers? School Teachers?

Tai is probably tailor.
WW - window washer?
con -constable?

I got the text from Ancestry a while back and I'm not a member there anymore so I can't access it to see the details. It looks like a list of heads of households in the county of Washington, Pennsylvania. Washington County was pretty sparsely populated at that time. It was south of Pittsburgh, mainly rural, lots of farmers. (This area was where the Whiskey Rebellion took place so I'm guessing they grew a lot of corn. ) There were some small towns and probably some industry. I'm not sure what the timeline is for that, I should check. They wouldn't have been slave holders since it was 1800 and Pennsylvania was never a slave state anyway.

Tai for tailor, con for constable. That makes sense!

It was gradually phased out after the formation of the USA. Because of this, there are a lot of very interesting slave records in the rural Pennsylvania counties - I just went through a number of them in Fayette and Cumberland counties. I would have to recheck, but I think that slaves born before 1780 were supposed to be slaves for life, "negro" or "mulatto" births were recorded from about this time, because children born after this date were to get their freedom from the age of 28. Thus, the slaveholders were required to register the births of negro and mulatto children under their authority. They are rather enlightening documents.

https://en.wikipedia.org/wiki/History_of_slavery_in_Pennsylvania

The absolute numbers are not large, yet still significant. What caught my attention was the high proportion of "mulatto" children; it seemed that it was nearly half, although may have been less than this. Then the question is, how much of this was out and out rape, and how much was effectively common law marriage prohibited by law. I suspect a great deal more of the former, but have no way to find out - although I think that it may be possible to discern some through various records.

The more one digs into the history of slavery in the United States, the more one finds one's preconceptions challenged. Society's views have been heavily formed by Hollywood rather than reality, and the laws around slavery hardened substantially in the decades leading up to the Civil War.

Also, relatively speaking, Washington County was fairly well populated by 1800.

My guess on the "st" is that it means "store keeper", although school teacher is hardly out of the question.

But duh, you're right, the north did have slavery early on.....You can tell I'm no history expert.

It didn't occur to me to look for slave owners in my PA lines because my eastern PA ancestors were anti-slavery Quakers and the western PA lines I've researched so far were mostly small farmers and didn't include any slave owners (from what I saw in the records). But I suppose it's possible with this line I'm looking into now, I just started researching them and don't know much about them yet.

I have generally found an Index to the abbreviations used toward the beginning of the directory itself. This link says St. Is an abbreviation for Store: http://www.genealogyintime.com/dictionaries/city-directory-abbreviations.html