The intellect, the rational faculty — what is highest in the human being. For the Stoics νοῦς is close to the TERMruling part and to the cosmic Logos: an individual intellect is a "fragment" (ἀπόσπασμα) of the divine reason diffused throughout the cosmos. Through νοῦς the human being shares in god, and through god in other human beings: the commonality of intellect is the ground of the TERMkinship of rational beings.

SVF I 87 (Zeno on the soul as pneuma); II 879, 885 (νοῦς as part of the world-soul); DL VII 138–139, 156–157; LS 53–54. In Marcus: Med. 2.1; 3.6; 5.27; 12.26.

In Marcus, νοῦς figures as the inner δαίμων — the guiding genius, the "god within us" (Med. 3.6; 5.27). In passage 02-01 it is precisely νοῦς (and not the narrower ἡγεμονικόν) that is named, because the point is what binds human beings together: their shared rationality as an ontological connection, not as an individual centre of decision. See TERMtheia-apomoira: the formula "sharing in intellect and the divine portion" applies not only to the sage but to every human being.