ester CHEBI:4859 Ester CHEBI:23960 CHEBI:35701 esters A compound formally derived from an oxoacid R<small>_<em>k</em></small>E(=O)<small>_<em>l</em></small>(OH)<small>_<em>m</em></small> (<em>l</em> > 0) and an alcohol, phenol, heteroarenol, or enol by linking with formal loss of water from an acidic hydroxy group of the former and a hydroxy group of the latter. chebi_ontology organooxygen compound