Model
Dictionary Definition
http://www.merriam-webster.com/dictionary/model
Committee Definition
An emulator used to describe a phenomenon
Domain Specific Usage
Computational Model: a function used to describe an observed phenomenon
Notes
ACM definition: http://www.acm-sigsim-mskr.org/glossary.htm#m
MSCO definition: http://www.msco.mil/documents/RPG/VV&A%20RPG%20Glossary%20of%20Terms.pdf