temper

Temper is a term with several related meanings in language and in technical fields. In everyday usage, it refers to a person’s mood or emotional state; a “hot temper” denotes quick anger, while “temperament” can denote characteristic patterns of behavior or personality.

The word derives from Latin temperare “to mix, regulate, or proportion,” and by extension to moderate or control something. In English, this has led to senses involving both emotional regulation and physical processes that alter material properties.

In psychology and everyday speech, temper describes a person’s emotional reactivity. “Temper” can be used as a noun for mood, or as a verb meaning to moderate one’s emotional response. Historically, temperaments were linked to humoral theory (blood, phlegm, black bile, yellow bile).

In materials science, tempering refers to heat-treatment processes. For metals, especially steel, heating to a certain temperature and quenching increases hardness, then tempering at a lower temperature increases toughness and reduces brittleness. Tempered metal thus balances hardness and ductility. In glass, tempering introduces surface compression to improve strength and safety; tempered glass is stronger but breaks into small fragments when shattered.

Other uses include cooking, where tempering means lightly heating ingredients to release flavors (spices or seeds in oil). In ceramics, tempering adds materials to clay to improve workability and reduce cracking. In chocolate, tempering refers to controlled crystallization of cocoa butter to achieve a glossy finish and stable texture.