Natyashastra
नता नतास्यालङ्कारबन्धे कण्ठावलम्बने , उन्नताभ्युन्नतमुखी ग्रीवा चोर्ध्वनिवेशने ॥ १७३॥
Natā is when the face is bent downward and is used in wearing ornaments and embracing the neck. Unnatā is when the face is upturned and is used in looking upwards.
english translation
natA natAsyAlaGkArabandhe kaNThAvalambane , unnatAbhyunnatamukhI grIvA cordhvanivezane ॥ 173॥
hk transliteration by Sanscript