Assuming the following pom.xml maven would build a client.war file which when deployed to Tomcat will have the URL www.server.com:8080/client
Since you're using the combination of eclipse, tomcat, and maven, I'm going to make the guess that the m2e-wtp plugin is in use here. There's a FAQ that addresses this. This also shows though how to change your context root in a maven specific way (using the war plugin for specifying a finalName for the war) which results in a correctly named war file (such as ROOT.war as mentioned in other answers.