Wiktionary:Word of the day/2025/February 13

1. (uncountable) Modification or regulation of something to achieve an appropriate measure or proportion; (countable) an instance of this.
   1. (art, uncountable) Variation (especially softening or toning down) of brightness, form, etc.; (countable) an instance of this.
   2. (biology, uncountable) Variation in the activity or form of a cell in response to changes in the environment; (countable) an instance of this.
   3. (engineering, physics, uncountable) Chiefly preceded by a descriptive word: modification of an electromagnetic wave or other oscillating carrier wave to apply a signal to it; (countable) an instance of this; also, the extent to which such a wave is modified; and the modified wave or signal.
   4. (music)
      1. (uncountable) Variation of the intensity, pitch, and tone of the sound of a musical instrument or voice; inflection; (countable) an instance of this.
      2. (uncountable) Changing of the key in a piece of music; also, the effect achieved by this as an element of harmony; (countable) an instance of this.
   5. (typography, countable) The contrast between the thick and thin parts of the strokes of a typeface.
2. (uncountable) Changing of a thing from one form to another; (countable) an instance of this.
3. (obsolete)
   1. (uncountable) Harmonious use of language in poetry or prose.
   2. (architecture, uncountable, rare) Modification of the parts of a classical Greek or Roman building to achieve appropriate proportions by measuring in modules (“standard units of measure, usually the diameter or radius of a column at the base of a shaft”).
   3. (music)
      1. (countable, Christianity) Any of the musical notes in ecclesiastical modes of music on which a melodic phrase had to begin and end.
      2. (uncountable) Arrangement or composition, or performance, of music in a certain key or mode; also (countable) a series of musical notes, chord, or tune analyzed according to a key or mode.
      3. (uncountable) Making music or singing; (countable) a melody, a tune; also (chiefly in the plural), a musical note.

We are having a holoalphabetic month—each day features a term starting with a different letter of the alphabet (and two numbers)! Today is World Radio Day, which is recognized by the United Nations to highlight the importance of radio for sharing information, promoting diversity of ideas, and reaching remote communities and vulnerable people, and its role in emergency communication during disasters. United Nations Radio was established on this day in 1946.