In Jain usage, Avaddha / Avadḍha is not a separate “part” of the Panchang like tithi or nakshatra. It is a Pachchakkhān (vow) timing used in the sequence Navkārshi, Porsi, Sāḍh Porsi, Purimaddha, Avaddha. It means after three prahars of daytime from sunrise — in simple words, later in the day than Purimaddha. ( jainqq.org)

So, if someone says “Avaddha in Panchang,” they usually mean the Jain fasting/vow timing shown in the Panchang, not a classical astrological limb of Panchang. ( jainsite.com)