| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison. |
palladium pal·la·di·um (pə-lā'dē-əm)
n.
Symbol Pd
A soft ductile metallic element occurring naturally with platinum, especially in gold, nickel, and copper ores, and used as a catalyst in hydrogenation. Atomic number 46; atomic weight 106.4; melting point 1,555°C; boiling point 2,963°C; specific gravity 12.02 (20°C); valence 2, 3, 4.
| palladium (pə-lā'dē-əm) Pronunciation Key
Symbol Pd A malleable, ductile, grayish-white metallic element that occurs naturally with platinum. It is used as a catalyst in hydrogenation and in alloys for making electrical contacts and jewelry. Atomic number 46; atomic weight 106.4; melting point 1,552°C; boiling point 3,140°C; specific gravity 12.02 (20°C); valence 2, 3, 4. See Periodic Table. |