Yirah means fear, awe, reverence, or dread. It appears about 45 times. The 'fear of the LORD' is a technical theological term for proper reverence and submission to God — the foundation of wisdom.
The 'fear of the LORD' is the foundation of wisdom (Proverbs 1:7), the beginning of knowledge, and the essence of true religion. It is not cringing terror but reverential awe — the appropriate human response to God's holiness that produces obedience, humility, and intimate relationship.