What does the cryptic crossword clue "Returning ship, poetically, is a national symbol (4)" mean?

The definition is "national symbol". The wordplay uses a reversal. reverse of KEEL = LEEK; definition: "national symbol" The answer is LEEK.

Returning ship, poetically, is a national symbol (4)

Guardian Cryptic #29459 | 25 Across | 2024-08-12 flower