Orientation is a plural or singular noun?
In a book on programming there is such statement
The concepts on which object orientation depend (abstraction, encapsulation, inheritance and polymorphism) will be explained.
Here is used the word depend instead as I think depends.
Is it just a typo or am I translating the statement incorrectly and the word depend is related to the word concepts?
No, your reading of the sentence is correct; the subject of "depend" has to be 'orientation"; therefore an s is needed at the end of "depend".