What does this explanation mean? [closed]

This is a dialog from The Graduate. 1967

-Where is Alan St?
-Alan st? It's 6 blocks up and 3 over.

• Cartesian coordinates (cities often being laid out in a block plan in the US) with the y axis ('up') needing to be specified, but really putting y before x. – Edwin Ashworth Sep 24 at 15:30

The explanation actually needs supplementary information to make it complete. Maybe the person in the scene is pointing in a specific direction or gesturing right or left. But without further context it means:

6 blocks up = 6 blocks straight in the direction indicated (probably north).

3 blocks over = (after going the 6 blocks above) 3 blocks to the left or right as indicated.

• Is it right to just add "left" or "right" to the sentence in order to be more specific? Can we combine "over" and "left or right" in one phrase at all? – Ihor Cherepynskyi Sep 24 at 13:44
• 'over' is one way or the other, and I assume the person giving directions is pointing or indicating. It would be unnatural to say '3 blocks over left' or '3 blocks over right', although you could say "3 blocks over to the left" if you want to include both words. Notice that 'over' would be redundant in that case. – kandyman Sep 24 at 13:56
• Thank you, kandyman. – Ihor Cherepynskyi Sep 24 at 14:06
• This direction would have to be accompanied by some deictic orientation -- a hand pointing, both participants facing the same way, etc. Otherwise up and over have no reference out of context. This is often a problem with people giving directions -- they have no idea that everybody doesn't share their frame of reference. – John Lawler Sep 24 at 16:22

A block = “a usually rectangular space (as in a city) enclosed by streets and occupied by or intended for buildings” and is also “the distance along one of the sides of such a block”.

Merriam Webster

... 6 blocks up and 3 blocks over” = move six blocks ahead and three blocks to the left or right (which of left or right is not defined by the phrase).