The term 'fall line' can refer to two different things. The first is a geographical feature, which is a line of hills or mountains that mark the boundary between two different regions. The second is a skiing term, which refers to the line that a skier takes down a slope. The crossword solutions for this term are 'OOPS' (4 letters) and 'TRICKORTREAT' (12 letters). 'OOPS' is an acronym for Out Of Position Skiing, which is a skiing technique used to navigate around obstacles on a slope. 'TRICKORTREAT' is a type of ski race in which competitors must complete a series of tricks and turns in order to win.