EN
The author of the article attempts to prove that the registration of lexical units may not be a simple task. Therefore, it is very important is to make thorough analyses of explored expressions. The author adopts the concept unit of language proposed by Andrzej Bogusławski (cf. Bogusławski 1976) and she registers a few Polish units of language including the phrase światło, namely: w świetle dnia, światło górne, światło świeci się, światło pali się, światło dochodzi gdzieś.