21-letter words containing t, r, e, m, o, l
- weinberg-salam theory — electroweak theory.
- well-ordering theorem — the theorem of set theory that every set can be made a well-ordered set.
- william the conqueror — ("the Conqueror") 1027–87, duke of Normandy 1035–87; king of England 1066–87 (son of Robert I, duke of Normandy).
- wilson's storm petrel — a small petrel, Oceanites oceanicus, that breeds in the Southern Hemisphere but ranges into the North Atlantic and Pacific oceans.
- worth someone's while — worth someone's time, consideration, etc.; profitable in some way
- 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.