The term 'Traffic Sign Warning' is composed of two crossword solutions, SLO and SLOW. SLO stands for 'SLOW' and is a three-letter word, while SLOW is a four-letter word that also means 'SLOW'. Together, these two words form a warning sign to alert drivers to SLOW down. This type of sign is commonly seen on roads and highways to remind drivers to reduce their speed in order to ensure the safety of other drivers and pedestrians.