'less' is actually an improved reimplementation of 'more'.

On my Mac, for example, 'less' and 'more‘ are hardlinked:

       $ find /usr/bin -samefile /usr/bin/less
       /usr/bin/less
       /usr/bin/more

And invoking 'less' as 'more' most probably makes less drop into a compatibility mode.

Also, 'man more' brings you to the less(1) page, which contains the following snippet:

       Less is a program similar to more (1), but which allows backward  movement
       in the file as well as forward movement.  Also, less does not have to read
       the entire input file before starting, so with large input files it starts
       up  faster  than text editors like vi (1).  Less uses termcap (or terminfo
       on some systems), so it can run on a variety of terminals.  There is  even
       limited  support  for  hardcopy terminals.  (On a hardcopy terminal, lines
       which should be printed at the top of  the  screen  are  prefixed  with  a
       caret.)