Two distinct angular clocks
The Positional Astronomy Centre’s Rashtriya Panchang explanation defines Yoga by the sum of the Sun’s and Moon’s sidereal longitudes in 27 equal 13°20′ parts. Karana uses 6° increments of the Moon’s gain in longitude on the Sun: two Karanas to each Tithi. The published name table gives the 27 Yoga and 11 Karana names used here.
These are calculated categories, not astronomical objects or fixed spans of clock hours. The sunrise labels depend on where you are; each geocentric changeover has one UTC instant. The method guide explains the cyclic and fixed Karanas, ayanamsa choice, and why two almanacs can disagree near a boundary.