This article discusses the definitions and scope of phraseology as a domain which is primarily lexical but which very much connects with grammatical issues. We discuss the gradual widening of the scope of phraseology, resulting from the emergence of data-driven, bottom-up analyses of large language corpora. We also note that statistical models of learning and usage-based models of language use converge to provide theoretical support for the claim that language use is to a considerable extent formulaic. An overview of empirical research which supports this claim is provided. We also examine the various schools of linguistic thought which blur the distinction between lexis and grammar, such as the Hallidayan concept of lexicogrammar, valency grammar, pattern grammar, and construction grammar. Our conclusion is that while these and other developments in the field of syntax acknowledge the role of lexis and even attach great importance to it, academic publications which cover typically lexical issues, especially with respect to second language acquisition and use, rarely acknowledge the crucial interconnection between lexis and grammar.