(mathematics) a function used to calculate the distance between two points. / (topology) a metric.

(historical) The main tower of a castle or fortress, located within the castle walls. / The food or money required to keep someone alive and healthy; one's support, maintenance.

(rare) Of, pertaining to, or characteristic of butter / (organic chemistry) Of, pertaining to, or derived from butyric acid or any of the isomeric univalent radicals of formula C₃H₇CO₂-

plural of heterophobe