Petal
来自Big Physics
early 18th century: from modern Latin petalum (in late Latin ‘metal plate’), from Greek petalon ‘leaf’, neuter (used as a noun) of petalos ‘outspread’.
wiktionary
From Ancient Greek πέταλον(pétalon), from πέταλος(pétalos, “broad, flat”), from Proto-Indo-European *peth₂-(“to spread out”), whence Latin pandō and Proto-Germanic *faþmaz(“embrace”) (English fathom).
etymonline
petal (n.)
"one of the individual parts of a corolla of a flower," 1726 (earlier petala, 1704), from Modern Latin petalum "petal" (17c.), from Greek petalon "a leaf; leaf of metal, thin plate," noun use of neuter of adjective petalos "outspread, broad, flat," from PIE root *pete- "to spread." Related: Petaline.