Dik refers to the ten directions in Ayurveda - the four cardinal directions (east, west, north, south), the four intermediate directions (northeast, northwest, southwest, southeast), and up and down. Dik is considered an eternal, omnipresent, and fundamental dravya (substance) in Ayurveda due to its qualities and effects. The directions impact activities like collecting herbs, sleeping, receiving treatment, and plant growth. Certain Ayurvedic procedures also involve directional movements.