正, an indicative character, originally meant: a foot is walking towards a destination. 正 is composed of 一, an indicative sign; and 止, a foot. 正 mainly serves as a phonetic component to form characters.
You may also want to check out the component 乏
Characters formed by the phonetic component 正
征、怔、佂、钲、聇、姃、眐、炡 with the same pronunciation zhēng
症、鴊、证、政、with the same pronunciation zhèng
整 zhěng, 阷 chēng
Characters formed by the semantic component 正
罡 gāng