Lexicon” will refer to the component of a NLP system that contains information (semantic, grammatical) about individual words or word strings.

The role of lexicons in natural language processing – ACM Digital Library

Sentiment lexicons are mappings from words to scores capturing the degree of the sentiment expressed by a given word.

On the Automatic Learning of Sentiment Lexicons
  • There are different kinds of lexicons for different things (Subjectivity Lexicon, Sentiment Lexicon, Emotion, Opinion), even different languages.
  • They can be manually constructed or automated.
  • Sentiment lexicons are an important source of features.

Lexicon Embeddings

Lexicon embeddings are derived by taking scores from multiple sources of lexicon datasets. Each lexicon dataset consists of key-value pairs, where the key is a word and the value is a list of sentiment scores for that word (e.g., probabilities of the word in positive, neutral, and negative contexts). A lexicon embedding is constructed by concatenating all the scores among the datasets with respect to a word. If a word does not appear in certain datasets, 0 values are an assigned in place. The resulting embedding is in the form of a vector v ∈ R^e, where e is the total number of scores across all lexicon datasets.

(Lexicon Integrated CNN Models with Attention for Sentiment Analysis)