tempering

1. To moderate or control.

   Temper your language around children.

2. To strengthen or toughen a material, especially metal, by heat treatment; anneal.

   Tempering is a heat treatment technique applied to metals, alloys, and glass to achieve greater toughness by increasing the strength of materials and/or ductility. Tempering is performed by a controlled reheating of the work piece to a temperature below its lower eutectic critical temperature.

3. To sauté spices in ghee or oil to release essential oils for flavouring a dish in South Asian cuisine.
4. To mix clay, plaster or mortar with water to obtain the proper consistency.
5. To adjust, as the mathematical scale to the actual scale, or to that in actual use.
6. (Latinism) To govern; to manage.
7. To combine in due proportions; to constitute; to compose.
8. To mingle in due proportion; to prepare by combining; to modify, as by adding some new element; to qualify, as by an ingredient; hence, to soften; to mollify; to assuage.
9. To fit together; to adjust; to accommodate.

noun

The act by which something is tempered.