What does the cryptic crossword clue "Sister to tempestuous Pre-Raphaelite co-founder (8)" mean?

The wordplay uses an anagram. anagram of SISTER + TO = ROSSETTI The answer is ROSSETTI.

Sister to tempestuous Pre-Raphaelite co-founder (8)

Independent Cryptic #1840 | 20 Down | 2025-06-01 flower