OSCAR3 markup displaying recognised chemical entities (CM). A mouse-over action on an annotated term displays the associated metadata, in this case for 2,5-dichlorobenzylamine, and displays an image representing the structure generated by the Chemistry Development Kit (CDK) [35–37] (right). OSCAR3 concentrated on the identification and interpretation of chemical entities in text (named entity recognition, NER). The primary purpose was to identify and extract the following types of object: chemicals (CM), ontology terms (ONT; looked-up from ChEBI [38–40], FIX  and REX etc.), reactions (RN; as identified by linguistic constructs, e.g. "methylated"), chemical adjectives (CJ) mainly formed from chemical nouns), enzymes (ASE) and chemical prefixes (CPR), highlighted in different colours. These concepts are maintained in OSCAR4.