This means "touching". Two blocks of memory are contiguous if one begins immediately after the first one ends.
This is the character that is used to mark the end of strings in C. It is written "\0" and has the ASCII value zero.
This means that the last element in an array is the null character. Strings in C are said to be null-terminated, and many string functions rely on this property.
This refers to things that apply to the current function but do not apply outside the current function call. For example, a local variable is a variable declared inside a function that disappears when the function returns.