What does "register against the face" phrase mean?

Question

I am referring to this particular phrase

registers against the face

which can be heard in this video:

https://www.youtube.com/timedtext_editor?action_mde_edit_form=1&v=oHRBtgNsrLk&lang=ru&bl=vmp&ui=hd&ref=player&tab=captions

some quotes:

• does show a taper from one end to the other we're going to be registering the
• square and the gauge against the tooth registration faces face mark and face
• the middle just for any belly just because we're going to be registering a router against that to make sure the surface of the Tenons are parallel to
• knife wall across here up onto this edge using the registration faces every
• registration faces these points will come out exactly
• on the shoulder just like that so this line is registered with this line
• Tenons so your tenon's gonna go you're gonna register against this face mark
• registered against the right face here run the gaze line run it on to the end here
• take it down and I keep this registered here watch this now so I'm going to take

and many other places that can be found by following the link:

• https://www.google.com/search?q="registers+against+the+face"

The dictionaries I checked fail to give the answer. What does "register against the face" mean in the context of woodworking and technical/mechanical stuff.

Answer 1

As long as my square is square and I'm using the right registration faces, these points will come out exactly on the shoulder, just like that, so this line is registered with this line.  Perfect. 

Here, "registration faces" represents the physical surface equivalent of "alignment marks".  The registration face on his cutting tool is the surface that is meant to glide along a straight edge.  The correct registration face on his combination square is the flat part of the anvil that he places in full contact with the flat edge of the board.  The surface of the board against which the anvil lies is also a registration face.  In the active voice, he registers the square against both the board and the knife.  He does this so he can score a clean line from exactly the right starting point in exactly the right direction.

When he says "so this line is registered with this line", he is indicating that the last scored line ends precisely where the first scored line began.  If the lines didn't register, that would mean that something is out of alignment. 

This Merriam Webster page indicates the applicable sense of the verb to register in its second definition as a verb: to make or adjust so as to correspond exactly.  This is very closely related to the eighth definition as a noun: a condition of correct alignment or proper relative position.  So, "registers against the face" means comes into full contact with the surface for the sake of measuring, adjusting or positioning things. 

It's a bit of jargon that jointery and printing happen to share.  Common co-locations include registered against a surface, registered along or with a line, registered at or to a point.