What is the meaning of ?

Yoneda embedding

a fish

The hiragana syllable (yo). Its equivalent in katakana is (yo). It is the thirty-eighth syllable in the gojūon order; its position is (ya-gyō o-dan, row ya, section o).

Indicates certainty, conviction, or emphasis.

Used as a vocative particle to address the topic in question: O.

: over, more than

: night, evening

: deposit, in advance

, : I, me

Source: wiktionary.org