n, pl  -ties  1  :  natural or normal function: as  a  :  a process (as digestion) that an organism carries on or participates in by virtue of being alive  b  :  a similar process actually or potentially involving mental function : specif  :  an educational procedure designed to stimulate learning by firsthand experience  2  :  the characteristic of acting chemically or of promoting a chemical reaction <the of a catalyst>  .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.