As a specialised language, the terminology of marine pollution by plastics and microplastics is composed mainly of technical-scientific terms from the field of marine ecology, along with general-language words used with a domain-specific meaning. Since there are few existing studies focusing on the linguistic-terminological aspects of ecology, this book analyses the nature, characteristics, and possible applications of the terminology of marine plastic pollution by observing its degree of technicity in different textual genres. To this end, a small but significant corpus of texts embracing three genres (scientific, informative and normative texts) was created and processed with the aid of a software for terminological extraction. Following the results of software analysis, this book shows that this specialised language is mostly used in an expert-to-expert communicative context, although some concepts are simplified and used in other communicative situations.