A set of vocabulary items (the lexicon)
The set of meaningful units is infinite. There are often ‘old’ (archaic, obsolete) words which remain in the language, especially in print. Some may be used by oder speakers; some may be recognised for their meaning in context but wouldn’t be ‘known’ in isolation.
The set of meaningful units in the lexicon is more or less finite, but not exactly the same for every speaker. Some meaningful units have only grammatical meaning, i.e. suffixes on words such as -ing, -s, -ed, -th and so on. So we distinguish between:
- lexical meaning and
- grammatical meaningful units.