Address line, 16 bit memory, and addresses

Question

What is an address line (memory), and how many addresses does one address line hold. This would be in a 16 bit memory

Answer 1

Usually "Address line" denotes the electrical connection between a single address bit of the CPU (after translation by a memory management unit from a virtual address to a physical address) and the memory. A 16-bit CPU usually has 16 address lines (if the physical memory space is not expanded by a memory management unit).
So, one address line alone could only address 2 addresses, because its state can only be be 0 or 1, and a processor with 16 address lines can address 2^16 addresses, i.e. 64k addresses.