Panchanga · योगः
Yoga — The 27 Sun-Moon Unions
Yoga (from yuj, "to join") is calculated from the combined longitudes of the Sun and Moon. There are 27 named Yogas, each believed to colour the day's general character.
Two Yogas to note
Vyatipata and Vaidhriti are traditionally considered inauspicious for starting new ventures, regardless of what else the Panchanga shows for that day.
See Karana for the next Panchanga element, or the full overview.