The last four of the twelve dhyānas; the auto-hypnotic, or ecstatic entry into the four states represented by the four dhyāna heavens, i. e. 四 空 處 supra. In the first, the mind becomes void and vast like space; in the second, the powers of perception and understanding are unlimited; in the third, the discriminative powers of mind are subdued; in the fourth, the realm of consciousness or knowledge) without thought is reached, e. g. intuitive wisdom. These four are considered both as states of dhyāna, and as heavens into which one who practices these forms of dhyāna may be born.

A Dictionary of Chinese Buddhist Terms, William Edward Soothill and Lewis Hodous

又名四無色定，即空無邊處定、識無邊處定、無所有處定、非想非非想處定。空無邊處定是修行人心想出離患難重重的色（色蘊物質）的牢籠，於是捨色想而緣無邊的虛空，做到心與空無邊相應；識無邊處定是行人又厭棄外在的虛空，於是捨虛空而緣內在的識，做到心與識無邊相應；無所有處定是行人又厭棄其識，而觀心識無所有，做到心與無所有相應；非想非非想處定是無麤想（非想）又非無細想（非非想），做到無所愛樂與清淨無為的境界。

陳義孝編, 竺摩法師鑑定, 《佛學常見辭彙》