Śrī Caitanya Caritamrta · Text Ādi 3.72
অদ্বৈত, নিত্যানন্দ—চৈতন্যের দুই অঙ্গ ।
অঙ্গের অবয়বগণ কহিয়ে উপাঙ্গ ॥ ৭২ ॥
advaita, nityānanda — caitanyera dui aṅga
aṅgera avayava-gaṇa kahiye upāṅga
Śrī Advaita Prabhu and Śrī Nityānanda Prabhu are both plenary portions of Lord Caitanya. Thus They are the limbs [aṅgas] of His body. The parts of these two limbs are called the upāṅgas.
Read this verse on Vedabase.ioThis verse has no purport; its meaning is explained by the verses around it.