Fused Deposition Modeling. The term fused deposition modeling and its abbreviation to FDM are trademarked by Stratasys Inc. The equivalent term fused filament fabrication (FFF), was coined by the members of the RepRap project to provide a phrase that would be legally unconstrained in its use. Found on http://reprap.org/wiki/Glossary
Frequency-division multiplexing. Technique whereby information from multiple channels can be allocated bandwidth on a single wire based on frequency. Compare with ATDM, statistical multiplexing, and TDM. Found on https://www.encyclo.co.uk/local/22803