HigherOrderMessaging, or HOM is the application of higher order techniques such as higher order functions to message-oriented languages.

A higher order messages takes another message as its argument, just like a higher order function takes another function as its argument.

A paper can be found here:  http://portal.acm.org/citation.cfm?doid=1146841.1146844 
Alternative location for those without ACM access:  http://www.metaobject.com/papers/Higher_Order_Messaging_OOPSLA_2005.pdf

-- MarcelWeiher