瑜伽師地論略纂 5.85

5.85

二、釋別名者，「空」者，生、法無我，性非有。「無願」者，不願求。「無相」者，《佛地論》第一說離十相：色、聲、香、味、觸、男、女、生、老、死。《涅槃經》第十三說十三相，於此加三：苦、樂、捨相。三摩地，義如前說。　「解脫」者，離縛義。或由緣此，離諸諦縛；或由起此，證無為解脫。依此二義，解脫之門名解脫門；或體無漏，解脫即門。

Second, the explanation of the specific names: "Emptiness" means that the non-self of sentient beings and phenomena is non-existent by nature. "Wishlessness" means not wishing for or seeking. "Signlessness": the Buddhabhūmi-śāstra fascicle 1 states that it is free of ten signs: form, sound, smell, taste, touch, male, female, birth, old age, and death. The Nirvāṇa-sūtra fascicle 13 states thirteen signs, adding three to these: the signs of suffering, pleasure, and equanimity. Samādhi has its meaning as explained before. "Liberation" means freedom from bondage. Either because, due to focusing on this, one is freed from the bondages of the truths; or because, due to giving rise to this, one realizes unconditioned liberation. Based on these two meanings, the door of liberation is named "liberation door"; or its essence is uncontaminated, and liberation is itself the door.