Definify.com
Webster 1913 Edition
Labellum
‖
La-bel′lum
(lȧ-bĕl′lŭm)
, Noun.
pl. L. 
Labella 
(lȧ-bĕl′lȧ)
, E. Labellums 
(lȧ-bĕl′lŭmz)
. [L., dim. of 
labrum 
lip.] 1. 
(Bot.) 
The lower or apparently anterior petal of an orchidaceous flower, often of a very curious shape. 
2. 
(Zool.) 
A small appendage beneath the upper lip or labrum of certain insects. 
Definition 2025
labellum
labellum
English
Noun
labellum (plural labella or labellums)

Showy Lady Slipper (Cypripedium reginae) has a pink labellum.
- The lower central petal of orchid flowers, usually developed to be showy and attract pollinators.
 
Synonyms
Translations
Translations
Latin
Etymology 1
From labrum (“lip”).
Noun
labellum n (genitive labellī); second declension
- a (little) lip
 
Inflection
Second declension.
| Case | Singular | Plural | 
|---|---|---|
| nominative | labellum | labella | 
| genitive | labellī | labellōrum | 
| dative | labellō | labellīs | 
| accusative | labellum | labella | 
| ablative | labellō | labellīs | 
| vocative | labellum | labella | 
Etymology 2
From lābrum (“basin”).
Noun
lābellum n (genitive lābellī); second declension
Inflection
Second declension.
| Case | Singular | Plural | 
|---|---|---|
| nominative | lābellum | lābella | 
| genitive | lābellī | lābellōrum | 
| dative | lābellō | lābellīs | 
| accusative | lābellum | lābella | 
| ablative | lābellō | lābellīs | 
| vocative | lābellum | lābella | 
References
- labellum in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
 - labellum in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
 - LABELLUM in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition, 1883–1887)
 - Félix Gaffiot (1934), “labellum”, in Dictionnaire Illustré Latin-Français, Paris: Hachette.