parliamentary under secretary UK /ˌpɑːləˈmɛntəɹi ˈʌndəˌsɛkɹətɹi/US /ˌpɑɹləˈmɛntəɹi ˈʌndɚˌsɛkɹəˌtɛɹi/ noun1 •A junior minister in certain government systems, particularly in the United Kingdom, who assists a senior minister (the Secretary of State) and represents the department in parliament.The newly appointed parliamentary under secretary answered questions regarding the new infrastructure policy in the House of Commons. formsparliamentary under secretaries