w

• 英文字母表的第二十三个字母，为辅音字母。是唯一名称（double-u）描述其形状的字母，代表唇软腭近音 /w/。常用作瓦特（物理）、西（方向）、宽大号（W）及化学元素钨的符号。

The twenty-third letter of the English alphabet and the eighteenth consonant, representing the voiced labio-velar approximant sound /w/. As a grapheme, 'W' is unique in English for being the only letter whose name ('double-u') describes its shape rather than representing a distinct sound. It functions as an abbreviation for watt in physics, a symbol for west on maps, a size designation for wide, and the chemical symbol for tungsten.

1. The twenty-third letter of the English alphabetA1formal

   The uppercase or lowercase character (W, w) that constitutes the twenty-third symbol in the Latin-based English alphabet, classified as a consonant. It represents a voiced labio-velar approximant. Its name, 'double-u', reflects its visual origin as a ligature of two U's or V's. It is a relatively new letter in the Latin alphabet, only becoming standard in English by the early modern period.

   英文字母表的第二十三个字母

   • The word 'water' begins with the letter W.
   • The letter W is often called 'double-u' in English.
   • In some fonts, W looks like two overlapping V shapes.
   • The NATO phonetic word for W is 'Whiskey'.
   • The silent W in 'write' and 'wrist' can confuse learners.

2. The symbol for watt in physicsB1formalscientific

   The uppercase letter W used as the international standard symbol for the watt, the SI derived unit of power, radiant flux, and mechanical energy transfer. One watt is defined as one joule per second (1 J/s). It is a measure of the rate of energy conversion or transfer. The unit is named after the Scottish engineer James Watt.

   瓦特（功率单位）

   • The light bulb consumes 60 W of electrical power.
   • The power output of the motor is 500 W.
   • One horsepower is approximately 746 W.
   • A kilowatt-hour is the energy used by a 1000 W device running for one hour.
   • The speaker system has a peak power of 2000 W.

3. An abbreviation for westA1formal

   The uppercase letter W used as the standard abbreviation for the cardinal direction west. It is found on compasses, maps, and weather reports. It is the direct opposite of E for east, and is fundamental for navigation and geographic orientation. It is commonly paired with other directions (NW, SW) for intermediate points.

   西（方向）

   • The wind is blowing from the W at 10 mph.
   • They moved W toward the setting sun.
   • The W wing of the hospital is under construction.
   • California is on the W coast of the United States.
   • The map shows a road heading due W.

4. A size abbreviation for wideA2informal

   The letter W used as a standard label, particularly in shoe sizing and clothing, to indicate a wide or extra-wide fit. It denotes a broader width than the standard medium. It is also used to specify the dimension of width in product specifications, construction plans, and technical drawings, often contrasted with H (height) and D (depth).

   宽版（W）

   • I need these boots in a size 9 W.
   • The shoe box was labeled 'W' for wide.
   • The table dimensions are W 150 cm x H 75 cm.
   • His feet are very broad, so he always looks for W sizes.
   • Please measure the W of the doorframe before buying the cabinet.

5. The chemical symbol for tungsten (wolfram)B2formalscientific

   The one-letter chemical symbol representing the element tungsten, atomic number 74. The symbol W comes from the element's German name, 'Wolfram'. Tungsten is a rare, exceptionally hard and dense refractory metal with the highest melting point of all metals (3422°C). It is used in light bulb filaments, welding electrodes, and heavy metal alloys.

   钨（化学元素符号）

   • Tungsten, symbolized by W, has the highest melting point of all metals.
   • The W filament in the light bulb glows white hot.
   • The name Wolfram gave rise to the chemical symbol W.
   • Drill bits tipped with W carbide stay sharp longer.
   • W is used in counterweights and radiation shielding due to its density.