21-letter words containing f, e, m, s, o
- warm silence software — A small company run by(?) Robin Watts, producing software for the Acorn Archimedes.
- william of malmesbury — William of, William of Malmesbury.
- xilinx netlist format — (language, electronics) (XNF) A Hardware Description Language for electronic circuit design, developed by Xilinx, Inc..
- yellow-fever mosquito — a mosquito, Aedes aegypti, that transmits yellow fever and dengue.