Yoga Sūtra Chapter Two verse 51
बाह्याभ्यन्तर विषयाक्षेपी चतुर्थः ॥५१॥
bāhya-ābhyantara-viṣaya-ākṣepī caturthaḥ ||51||
The fourth transcends the external and internal as an object.
bāhya - externalābhyantara - internalviṣaya - objectākṣepīn - transcendscaturtha - fourth