
1) Castle architecture 2) Defence 3) Defense 4) Defensive structure
Found on
https://www.crosswordclues.com/clue/outwork

An outwork is a minor defense, fortification, built or established outside the principal fortification limits, detached or semidetached. Outworks such as ravelins, lunettes (demilunes), and caponiers to shield bastions and fortification curtains from direct battery were developed in the 16th century. Later the increasing scale of warfare and the g...
Found on
http://en.wikipedia.org/wiki/Outwork

• (n.) A minor defense constructed beyond the main body of a work, as a ravelin, lunette, hornwork, etc. • (v. t.) To exceed in working; to work more or faster than.
Found on
http://thinkexist.com/dictionary/meaning/outwork/
Out'work` noun (Fort.) A minor defense constructed beyond the main body of a work, as a ravelin, lunette, hornwork, etc.
Wilhelm. Found on
http://www.encyclo.co.uk/webster/O/48
Out·work' transitive verb To exceed in working; to work more or faster than.
Found on
http://www.encyclo.co.uk/webster/O/48

In fortifications outworks are minor defences constructed beyond the main body of a work. Examples include ravelin, lunette, hornwork, etc.
Found on
http://www.probertencyclopaedia.com/browse/FO.HTM

[
n] - subsidiary defensive structure lying outside the main fortified area
Found on
http://www.webdictionary.co.uk/definition.php?query=outwork

Work or services that are performed by an outside contractor or service provider.
Found on
https://www.encyclo.co.uk/local/20631
noun subsidiary defensive structure lying outside the main fortified area; `the outworks of the castle`
Found on
https://www.encyclo.co.uk/local/20974
No exact match found.