What does the ampersand indicate in this bash command 1>&2

Question

Quick one, 2>&1 redirects stderr to stdout, but what does the ampersand mean? I know if we had 2 > 1 it would output to a file named

Answer 1

It copies file descriptor 1 to file descriptor 2. FD2 is stderr and FD1 is stdout, so it makes any output to stderr go to stdout instead.