Unfortunately, most normal dictionaries are not very useful for the translation of surveying related technical terms. So for some things I don't know the English word.
The first things which come into my mind are these two tools:
This is the first one: http://upload.wikimedia.org/wikipedia/commons/f/f2/Doppelpenta.jpg
It is made of two pentagon prisms and it is used to determine right angles. Usually it is used together with a plumb bob.
It was once a very important tool when the so called "orthogonal method" was in use for German cadastral surveys: A baseline was defined by two control points (often established by a traverse), and for every point the distance along this line and the offset from this line was measured (with a chain or later with a steel tape) and recorded. The advantage was, that a theodolite was necessary only for the traverses; the later surveys could be done with simple tools as long as the control points where still in place.
Nowadays (after EDM and total stations came into use) the "polar method" using a total station came into use, but this tool is still useful sometimes, for example for an indirect measurement to a point not visible directly from the total station.
The second tool I don't know the English name for is this: http://upload.wikimedia.org/wikipedia/commons/0/03/Lattenrichter.jpg
It is used to hold i.e. a prim pole or a leveling rod vertically. (You could use a plumb bob, but this way it's easier.)
It would be nice if someone here could help me.