crystal

crystal — noun

1. a very clear, high-quality type of glass. Its surface is often cut into patterns

1.nounB1
Definition

a very clear, high-quality type of glass. Its surface is often cut into patterns that reflect light, and it is used to make drinking glasses, bowls, and decorative objects.

Example

The dining table was set with crystal glasses that sparkled in the candlelight.

uncountable noun for glass material

Aunt Rosa brought out her crystal vase for the anniversary flowers.

Common collocations
  • crystal glass
  • crystal vase
  • crystal chandelier
  • cut crystal
  • crystal clear
Synonyms
  • glass

    much broader; ordinary glass is not cut or as clear as crystal

  • lead crystal

    specific type of crystal containing lead oxide for extra brilliance

Usage Note

As an uncountable noun, crystal refers to the material itself (“a vase made of crystal”). As a countable noun, it refers to a single object (“three crystal—” often ellipsis).

2. the transparent protective window positioned over a timepiece’s dial. It is made

2.nounB2
Definition

the transparent protective window positioned over a timepiece’s dial. It is made from glass, acrylic, or synthetic sapphire and shields the hands and numerals from scratches, dust, and moisture.

Example

The crystal on Ezra’s watch cracked after he bumped it against the door frame.

A scratch on the crystal can make the whole watch face hard to read.

definite article: the crystal (specific part of the watch)

Common collocations
  • cracked crystal
  • replace the crystal
  • scratch-resistant crystal
  • sapphire crystal
Synonyms
  • watch glass

    less common; used mainly in older or technical descriptions

  • face cover

    non-technical description rather than a true synonym

Usage Note

In watch repair and sales contexts, “crystal” is the standard term for this part; “glass” is sometimes used informally.

3. a tiny, solid fragment of a chemical that has taken on an orderly, multi-sided s

3.nounB2
Definition

a tiny, solid fragment of a chemical that has taken on an orderly, multi-sided shape through natural processes. These fragments appear when a liquid freezes, a solution evaporates, or a vapour turns directly into a solid.

Example

The lab technician watched sugar crystals form as the syrup cooled.

Ife collected salt crystals from the edge of the dried-up tide pool.

countable: individual crystal pieces

Common collocations
  • sugar crystals
  • ice crystals
  • salt crystals
  • crystal formation
  • grow crystals
Synonyms
  • grain

    smaller and less regular in shape; used for particles like sand or sugar

  • solid

    much broader; any solid substance, not necessarily crystalline

Usage Note

This sense is the everyday meaning of crystals as small, visible, solid forms. Distinguish from sense 4, which describes the scientific atomic structure of any crystalline solid.

4. any solid substance in which atoms, molecules, or ions sit at fixed positions th

4.nounC1
Definition

any solid substance in which atoms, molecules, or ions sit at fixed positions that repeat in all three directions, forming a regular grid known as a lattice. Most metals, minerals, salts, and semiconductors belong to this category.

Example

In physics class, the students learned how X-rays reveal the crystal structure of metals.

A single crystal of silicon can be sliced into thin wafers for computer chips.

countable: a single continuous piece with ordered structure

Common collocations
  • crystal structure
  • crystal lattice
  • single crystal
  • crystal growth
  • X-ray crystallography
Synonyms
  • crystalline solid

    the formal scientific term; “crystal” is the shortened everyday form

  • lattice structure

    refers specifically to the repeating arrangement rather than the material itself

Antonyms

Usage Note

Frequently used in scientific contexts: materials science, mineralogy, solid-state physics. The uncountable form (“crystal” as a category) is common: “The sample is a form of crystal.”

5. a clear, colourless mineral, most commonly quartz, that is cut and polished for

5.nounB1
Definition

a clear, colourless mineral, most commonly quartz, that is cut and polished for use in jewellery, ornaments, or believed by some to have healing or calming properties.

Example

Padma wore a clear crystal pendant around her neck during the meditation retreat.

The shop sold crystal beads, amethysts, and polished stones from Brazil.

uncountable: crystal as a type of mineral material

Common collocations
  • crystal necklace
  • crystal healing
  • quartz crystal
  • crystal ball
  • clear crystal
Synonyms
  • quartz

    the specific mineral; crystal is a broader term that can include other minerals

  • rock crystal

    traditional name for colourless quartz used in jewellery

  • gemstone

    broader category; not all gemstones are clear or crystalline

Usage Note

When used uncountably (“set in crystal”), it refers to the mineral material. When countable (“a crystal”), it refers to a single cut or natural piece.

6. a slang term for the illegal drug methamphetamine, especially in its solid, crys

6.noun
Definition

a slang term for the illegal drug methamphetamine, especially in its solid, crystalline form that is smoked or injected.

Example

The documentary followed three families in rural Tennessee whose sons had fallen into crystal addiction.

Police in Marshall County reported that crystal-related arrests had doubled since the steel mill shut down.

informal register; compound adjective crystal-related

Common collocations
  • crystal meth
  • crystal addiction
  • crystal use
  • crystal-related
Synonyms
  • crystal meth

    the full informal name; slightly more specific than “crystal” alone

  • methamphetamine

    the formal chemical name; neutral register

Usage Note

Always uncountable in this sense. Very informal and restricted to contexts about drug abuse, crime, and public health. Often appears in the compound “crystal meth.” Avoid in formal or polite conversation.

Common Mistakes

She bought crystal for her chandelier’ (when meaning the drug).
She bought crystal meth’ or specify context clearly.
The drug sense is informal slang; without ‘meth’ the meaning may confuse readers.

7. a small, precisely cut piece of crystalline material, typically quartz, that vib

7.nounC1
Definition

a small, precisely cut piece of crystalline material, typically quartz, that vibrates at a stable frequency when electricity passes through it. Used in watches, radios, and computers to keep accurate time or control signals.

Example

The quartz crystal inside Yuna’s digital watch vibrates 32,768 times every second to keep the time accurate.

The engineer replaced the damaged crystal on the circuit board to restore the signal.

definite article: the specific component on the board

Common collocations
  • quartz crystal
  • crystal oscillator
  • timing crystal
  • crystal resonator
Synonyms

Usage Note

Technical term in electronics. Also referred to as a “quartz crystal” or “timing crystal.” The frequency stability of the crystal makes it essential for precision timing.

crystal — adjective

crystal — idiom

Word family

  • crystalline
    adjectiveB2
  • crystallize
    verbB2
  • crystallization
    nounC1
  • crystallized
    adjectiveB2
  • crystallography
    nounC2

Synonym discussion

Sense: noun/5

All four words refer to minerals used in jewellery, but they differ in specificity. “Quartz” is the most precise mineralogical term — it names a specific silicon dioxide mineral that forms in many colours including clear (rock crystal), purple (amethyst), and yellow (citrine). “Crystal” is broader: it can refer to quartz but also to any clear, faceted mineral, and even to man-made glass in the jewellery trade. “Rock crystal” is the traditional name for colourless, transparent quartz, used especially in jewellery and ornament contexts. “Gemstone” is the broadest category of all, covering any mineral (diamond, ruby, sapphire, emerald, etc.) that is cut and polished for adornment. For example: a jeweller might say “This necklace is set with quartz crystals,” but only a clear, colourless piece would be called “rock crystal.” A “gemstone” can be any colour and any mineral, whereas “crystal” in the jewellery sense usually implies some degree of transparency.

quartz ↗crystal ↗gemstonerock crystal

Common collocations

Nouns

  • crystal glass
  • crystal structure
  • crystal lattice
  • crystal formation

Phrases

  • crystal clear

Prepositions

  • crystal of
  • crystal in
  • crystal with

Etymology

GreekLatinFrenchEnglish

The word “crystal” comes from the ancient Greek word “krystallos” (κρύσταλλος), which meant “ice.” The Greeks believed that rock crystal found in the mountains was a form of ice that had frozen so completely that it could never melt. This idea was based on the stone’s perfect transparency and coldness to the touch. The Greek word passed into Latin as “crystallum” (meaning both ice and rock crystal), then into Old French as “cristal,” and finally into Middle English. The modern spelling with “y” was influenced by the Latin form.