My dictionary AND your own pull down definition says that "la poesía" can mean the poem, so why is the marked as incorrect?
I am Spanish and I'd say "el poema" for "the poem" though tbh I'm not sure if it is valid to call poesía a poem, at least in Polish it is said that way but I never found myself in a situation to look if it is valid in Spanish... (but TL;DR: it probably is valid)
I wish I could mark some words as known or please stop showing me the same words all of the time!
Manzanas anyone? Officially DL's favourite fruit. Estoy harto de las manzanas.
Both are correct. "El poema" and "la poesía" can mean "the poem", and "la poesía" can also mean "the poetry".
I find that in English, Spanish finds a common ending for words. In this case the root at hand is poe- looking for an ending like -m, or -try. The Spanish equivalent to -try is -ia. This, however, is my own speculation from others like:
-y to -ia -ity to -idad
If this does not suit your need for an answer. Perhaps, they use a different word to describes something better for themselves. For example, in English we say 'Christmas Tree'. Germans say 'Tenenbaum'.
The drop down solutions include "poem", so my answer should have been accepted.
Without context hinting otherwise, I would recommend using poema for a single piece and poesía for the discipline.
So a year later (2/24/18), DL is still marking 'the poem' incorrect, even though both the dictionary and their drop-down memo show that 'the poem' is correct.