22-letter words containing h, e, a, t, d
- whitworth screw thread — a thread form and system of standard sizes, proposed by Whitworth in 1841 and adopted as standard in the U.K., having a flank angle of 55° and a rounded top and foot
- yellow-shafted flicker — a North American woodpecker C. auratus, which has a yellow undersurface to the wings and tail
- ysbaddaden chief-giant — the father of Olwen.