What is a lexical (ontology) label?

Here’s an explanation of the different types of labels.

What is a label?

Labels (or Lexical Labels) are the way to connect an element of language to your class. You should add the word simplest form (the lemma) as the label so that Lettria can understand all variants of the word.

There are three types of lexical labels: Preferred Labels, Alternative Labels, and Hidden Labels.

Preferred labels​

A preferred label is the main word or group of words used to designate things or concepts belonging to a specific class.

You can define only one preferred label per language and per class.

The preferred label can be different from the class name.


In the image example, we defined light bulb as preferred label for English and ampoule for French.

Alternative labels​

An alternative label can be a different spelling of the preferred label, an abbreviation of the preferred label, an exact synonym of the preferred label but not a word or token of close meaning.


In the image above, we added different ways to refer to the light bulb in English: lamp bulbbulb and lightbulb.

Hidden labels​

Hidden labels are other words or groups of words that can designate things or concepts belonging to a class, but which are considered inappropriate, such as misspelled words or slang words.


In the image above, we added light blub as hidden label in English because of the misspel of bulb and empoule in French for the misspel of ampoule.

How it works in Lettria

When Lettria analyses the following two sentences:

  • A light bulb dangled from a wire in the ceiling
  • Normal light bulbs emit more red than blue light

It detects that even if two different words are used (bulb, light bulbs), it refers to the same concept.

If you need more help, please reach out to us at hello@lettria.com