Patanjali Yog Sutra
तस्य वाचकः प्रणवः ॥१-२७॥
The signifier of that( God) is Pranava or Om (the universal sound).
english translation
उस ईश्वर का वाचक (नाम) प्रणव अर्थात् ॐ कार है ।
hindi translation
tasya vAcakaH praNavaH ॥1-27॥
hk transliteration by Sanscript