The article explores the least studied and, thus, the most disputable and variable aspect in describing phraseological units, which is semantics. The research is based on the semantic and grammatical analysis of phraseological units with a zoonymic component in the English language collected by means of continuous sampling from the English-Russian phraseological dictionaries by professor A.V. Kunin. This is an essential part in the long process of compiling a dictionary of phraseological units.