labellum

< /ləˈbɛl ə/. Botany.

1. the petal of an orchid that differs more or less markedly from the other petals, often forming the most conspicuous part; the lip.

noun plural -la (-lə)

1. the part of the corolla of certain plants, esp orchids, that forms a distinct, often lobed, lip
2. a lobe at the tip of the proboscis of a fly