A school zone sign is a traffic sign that indicates the presence of a school in the area. It is usually accompanied by a speed limit sign, which is meant to remind drivers to SLOW down when they are near a school. The crossword solutions for the term SCHOOL ZONE SIGN are SLO (3 letters) and SLOW (4 letters). SLO stands for 'SLOW' and SLOW is an abbreviation for the same word. Both terms are used to remind drivers to reduce their speed when they are near a school.