Crossword Genius

Flyer from member of Trinity finally spending term inside (8)

Ross

I believe the answer is:

songbird

I'm a little stuck... Click here to teach me more about this clue!

'flyer' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for songbird that I've seen before include "Nightingale, for example" , "Thrush or canary, say" , "Eg, warbler" , "Lark, for example" , "Melodious avian" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app