Hypolemma
http://lila-erc.eu/ontologies/lila/Hypolemma an entity of type: Class
A Hypolemma is a Form that is used (or may be used) by a Lemmatizer to lemmatize a token. However, this form can also be analyzed as an inflected (or otherwise derived) form of a another Lemma.
De-adjectival adverbs (e.g. "vehementer") and participles used adjectivally (even frequent ones, like "mortuus") are prototypical examples.