Abarim Publications' online Biblical Hebrew Dictionary
מעד
The verb מעד (ma'ad) means to slip, slide or totter. It's used about nine times in the Bible and describes a being unstable or insecure in one's confidence (i.e. "loins" Ezekiel 29:7, Psalm 69:23) or step (Psalm 26:1, 37:31), and hence tends to occur in combination with רגל (regel), feet (Job 12:5, Psalm 18:36, Proverbs 25:19).