This work describes the Agile and Continuous Integration for Modular Ontologies and Vocabularies (ACIMOV) ontology engineering methodology for developing ontologies and vocabularies. ACIMOV extends the SAMOD agile methodology to (1) ensure alignment to selected reference ontologies; (2) plan module development based on dependencies; (3) define ontology modules that can be specialized for specific domains; (4) empower active collaboration among ontology engineers and domain experts; (5) enable application developers to select views of the ontology for their specific domain and use case. ACIMOV adopts the standard git-based approach for coding, leveraging agility and DevOps principles. It has been designed to be operationalized using collaborative software development platforms such as Github or Gitlab, and tooled with continuous integration and continuous deployment workflows (CI/CD workflows) that run syntactic and semantic checks on the repository, specialize modules, generate and publish the ontology documentation.