IntroductionComputational Terminology covers an increasingly important aspect in Natural Language Processing areas such as text mining, information retrieval, information extraction, summarisation, textual entailment, document management systems, question-answering systems, ontology building, etc. Terminological information is paramount for knowledge mining from texts for scientific discovery and competitive intelligence. Scientific needs in fast growing domains (such as biomedicine, chemistry and ecology) and the overwhelming amount of textual data published daily demand that terminology is acquired and managed systematically and automatically; while in well established domains (such as law, economy, banking and music) the demand is on fine-grained analyses of documents for knowledge description and acquisition. Moreover, capturing new concepts leads to the acquisition and management of new knowledge.The aim of this fourth CompuTerm workshop is to bring together Natural Language Processing researchers to discuss recent advances in computational terminology and its impact in many NLP applications. The topics addressed in this workshop are wide ranging:• term extraction, recognition and filtering, which is the core of the terminological activity that lays basis for other terminological topics and tasks;• event recognition and extraction, that extends the notion of the terminological entity from terms meaning static units up to terms meaning procedural and dynamic processes;• acquisition of semantic relations among terms, which is also an important research topic as the acquisition of semantic relationships between terms finds applications such as the population and update of existing knowledge bases, definition of domain specific templates in information extraction and disambiguation of terms;• term variation management, that helps to deal with the dynamic nature of terms, their acquisition from heterogeneous sources, their integration, standardisation and representation for a large range of applications and resources, is also increasingly important, as one has to address this research problem when working with various controlled vocabularies, thesauri, ontologies and textual data. Term variation is also related to their paraphrases and reformulations, due to historical, regional, local or personal issues. Besides, the discovery of synonym terms or term clusters is equally beneficial to many NLP applications;• definition acquisition, that covers important research and aims to provide precise and nonambiguous description of terminological entities. Such definitions may contain elements necessary for the formal description of terms and concepts within ontologies;• consideration of the user expertise, that is becoming a new issue in the terminological activity, takes into account the fact that specialized domains contain notions and terms often nonunderstandable to non-experts or to laymen (such as patients within the medical area, or bank clients within banking and economy areas). This aspect, although related to s...