labellum
noun
la·bel·lum lə-ˈbe-ləm 
plural labella lə-ˈbe-lə
1
: the median and usually most morphologically distinct member of the corolla of an orchid
2
: a terminal part of the labium or labrum of various insects
Example Sentences
Recent Examples on the Web The sepals, which are pink, petal-like extensions of the flower, look like wings while the lip (or labellum) mimics the body of a bee. 
Patricia Shannon, Southern Living, 30 Apr. 2020 The slipper orchids had brightly colored labellum surrounded by two massive petals and were about the size of a hand, fairly large for an orchid. Katy Kelleher, Longreads, 9 Oct. 2019
Patricia Shannon, Southern Living, 30 Apr. 2020 The slipper orchids had brightly colored labellum surrounded by two massive petals and were about the size of a hand, fairly large for an orchid. Katy Kelleher, Longreads, 9 Oct. 2019 Word History
Etymology
New Latin, from Latin, diminutive of labrum lip — more at lip
First Known Use
1810, in the meaning defined at sense 1