I may have made this term up myself; I am on the go and can't check it. As I use the expression "lexical typing", it means that the type of a variable can be ascertained from examining the text of the program, without needing to run it. Python is strongly typed, but dynamically typed: you can only know for sure the type of a value by checking the value at runtime.

This by analogy with "lexical scoping", where you know where a certain name will be bound just by looking at the program's text, while with dynamic scoping, the stack is what determines where a variable is bound, and you can only know about it at runtime.

I guess I should have said "static typing". I probably made the mistake because lexical scoping is also called static scoping, and I was writing in a hurry.