| a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
alkylation al·kyl·a·tion (āl'kə-lā'shən)
n.
A process in which one or more alkyl groups are substituted for hydrogen atoms in an organic compound.