High machinery
A sign that reads, highway intersection 1000ft means that in a 1000 feet, you will come upon this intersection. This signs are put along roads to inform drivers.
Watch for highway machinery Watch for cross traffic and traffic turning onto or off of the highway.
Tebin ahead
+ (a plus sign) is the symbol for an intersection.
Farm to market road
It means that people coming from all directions into the intersection have STOP signs, not just you.
how close to a stop sign, or an intersection can I park
That sign would be the stop sign, the 4-way sign tell you that at that intersection, 4 of the directions of travel through the intersection (including yours) have a stop sign.
The straight road you are on ends at a "T" intersection (road that goes right and left).
letters don't specifically have a definition. 'H' means 'H'. if you mean when you drive on a highway and you see a sign that says 'H' it means hospital.
An intersection with no stop sign indication means you have the right of way, this also means that the drivers on the other side of the intersection have a stop sign. But to be safe,you can always slow down, just to be ready to break if a driver thinks you have a stop sign.
JCT on a highway sign means "junction." That is, a sign that says "JCT US 35 15 miles" means that in 15 miles you will either cross or merge with US highway 35.