Both of these are primary from the old printing days.
Carriage return is from the days of the teletype printers/old typewriters, where literally the carriage would return to the next line, and push the paper up. This is what we now call \r.
Line feed LF signals the end of the line, it signals that the line has ended - but doesn't move the cursor to the next line. In other words, it doesn't "return" the cursor/printer head to the next line.
For more sundry details, the mighty wikipedia to the rescue.