fundir

Fundir is a verb in Spanish and Portuguese with senses centered on changing a substance from a solid into a liquid or on joining materials into a single mass. The core meaning is to melt or fuse by applying heat, as in heating metal until it becomes liquid or melting solids such as chocolate, butter, or cheese. The reflexive form fundirse describes both physical fusion and figurative or mechanical failure, for example, a metal part fusing together or a light bulb se fundió (burned out).

In metallurgy and materials processing, fundir refers to the melting of metals to produce liquid metal that can be cast or alloyed. The term is closely linked to the word fundición, which denotes a foundry or the process of melting and casting metal. In everyday language, fundir is also used to describe the act of melting substances in cooking or the outcome of overheated equipment, as in "se fundió la bombilla."

In Portuguese, fundir shares the same primary meanings: to melt or fuse materials, to merge entities, and to become liquid through heating. Related nouns include fundição (foundry) and fundido (melted, fused; also a culinary term for melted cheese or chocolate). The adjective fundido describes a substance that has been melted or fused.

Etymology traces fundir to Latin fundere, meaning to pour or cast, a path that evolved in Romance languages to encompass melting and fusing processes. The term is widely used in technical contexts as well as in everyday speech.