(organic chemistry) An organic compound related to choline, with the difference that the terminal carboxylic acid group of trimethylglycine has been reduced to a hydroxyl group in choline.

(transitive, intransitive, UK) To alternate with each other, often in the same post or location. / (transitive, intransitive, UK) To alternate between two people.

Any antigen that stimulates autoantibodies in the organism that produced it; an antigen produced by the self (that is, by one's own tissues).

The decade from 1820 to 1829.