He (breath) is Udgitha. Breath verily is Ut, for by breath this universe is upheld (uttabdha); and speech is Githa, song. And because he is ut and githa, therefore he (breath) is Udgitha.

In plain words: Breath is also the Udgitha, the main chant sung at a sacrifice. "Ut" stands for breath, which holds up the whole world, and "githa" means song, which is speech. Together they make the word Udgitha.