សន្យា (Khmer) comes from Thai สัญญา, from Pali saññā, from Sanskrit संज्ञा, from Sanskrit ज्ञा, from Proto-Indo-Aryan ȷ́naH-, from Proto-Indo-Iranian ǰnaH-, from Proto-Indo-European ǵneh₃- — to know.
សន្យា (Khmer): to promise, agree, pledge