A LaTeX package defining "abbreviation macros," which expand to defined text and insert following space intelligently, based on context. They can also expand to one thing the first time they are used and another thing on subsequent invocations. Thus they can be abbreviations in two senses, in the source and in the document. Also includes a facility for suffixes like 1900\BC and 6:00\PM which correctly handles following periods. The author is Matt Swift.