軌き道どう長ちょう半はん径けいMeaningsNoun1. semi-major axis (esp. in orbital matters)Kanji used軌tracks道roadway長long半half径diameterComposed of軌き道どうorbit; trajectory; (railroad) track; (right) track; proper courseNoun長ちょうhead; chief; leader; elder; merit; strong point; superiority; majorNoun半はん径けいradiusNoun