Bhagavad Gita 5.27

स्पर्शान्कृत्वा बहिर्बाह्यांश्चक्षुश्चैवान्तरे भ्रुवोः।प्राणापानौ समौ कृत्वा नासाभ्यन्तरचारिणौ॥

sparśānkṛtvā bahirbāhyāṃścakṣuścaivāntare bhruvoḥ |prāṇāpānau samau kṛtvā nāsābhyantaracāriṇau ||

Shutting out all external contacts and fixing the gaze between the eyebrows, realizing the outgoing and incoming breaths moving within the nostrils.

Excluding external objects, with his gaze fixed between the eyebrows, and the inward and outward breathings passing equally through his nostrils;

Our plain-language meaning of this verse is waiting for scholar review.