यत् देहे अहंकारं करोति, गृहादिषु ममकारं करोति, इन्द्रियद्वारा बहिर्गच्छति, तत् कारणस्वरूपं मनः।
What is the manas
The mind is that cause, which harbors a sense of ego toward the body; harbors attachment toward house etc; and which moves outwards by operating through the senses.