lewis

lewis — noun

1. a chemical substance that can take a lone electron pair offered by another subst

1.nounC2
Definition

a chemical substance that can take a lone electron pair offered by another substance (a Lewis base) and use that pair to create a new covalent bond. Unlike traditional acids, a Lewis acid does not need to release hydrogen ions.

Example

Boron trifluoride acts as a Lewis acid when it accepts electrons from ammonia.

collocation: act as a Lewis acid

The chemistry teacher explained that a Lewis acid must have an empty orbital to receive electrons.

grammar pattern: Lewis acid + must + infinitive

Common collocations
  • Lewis acid catalyst
  • Lewis acid-base reaction
  • strong Lewis acid
  • hard Lewis acid
Synonyms
Antonyms
  • Lewis base

    the substance that donates the electron pair in the reaction

Usage Note

Almost always capitalised because it is named after the chemist Gilbert N. Lewis. Frequently appears in the paired phrase 'Lewis acid and Lewis base'. The key structural feature is an empty orbital that can accept an electron pair.

Common Mistakes

A Lewis acid gives away protons.
A Lewis acid accepts electron pairs.
the definition is about electron-pair acceptance, not proton donation (that is a Brønsted acid).
The Lewis acid in the battery leaked.
The acidic electrolyte in the battery leaked.
'Lewis acid' is a theoretical classification, not a common household substance.

2. a set of three iron wedges that fit together inside a specially cut dovetail-sha

2.nounC2
Definition

a set of three iron wedges that fit together inside a specially cut dovetail-shaped hole in a large block of stone. When a crane chain is attached to the top ring of the device, the wedges grip the stone tightly so it can be lifted safely.

Example

The stonemason cut a dovetail hole in the granite block to receive the lewis.

collocation: cut/receive a lewis

Workers inserted the three iron wedges of the lewis into the stone before hooking up the crane.

collocation: insert the wedges of the lewis

Common collocations
  • insert a lewis
  • lewis hole
  • steel lewis
  • lifting lewis
Synonyms

Usage Note

A highly specialised term found almost exclusively in stonemasonry, heritage building restoration, and quarrying contexts. Also called a 'lewis bolt' or 'lewis pin' in some regional dialects. The device is named after the person who popularised its design, though the exact origin is debated.

Common Mistakes

He tied a rope around the lewis.
He attached the crane hook to the ring of the lewis.
a lewis has a ring or eye at the top; you do not tie a rope around it.
The lewis is a type of hammer.
The lewis is a lifting device, not a striking tool.
a common confusion because both are used in stonemasonry.

lewis — noun

1. the surname of several notable people in literature, science, exploration, and p

1.noun
Definition

the surname of several notable people in literature, science, exploration, and public life. Listed below are seven prominent figures who share this name.

Example

C.S. Lewis wrote The Chronicles of Narnia, a series beloved by children around the world.

C.S. Lewis — British author

Meriwether Lewis led the famous Lewis and Clark Expedition across the American West in 1804.

Meriwether Lewis — American explorer

Idioms

Cecil Day-Lewis / day-lewis

idiom

a cross-reference meaning 'see the entry for day-lewis'. Cecil Day-Lewis (1904–1972) was an Irish-born British poet who served as Poet Laureate, and his surname is sometimes listed under the compound form day-lewis.

If you look up day-lewis in this dictionary, you will find the entry for the poet Cecil Day-Lewis.

Word family

  • Lewis acid
    nounC2
  • Lewis base
    nounC2
  • lewis (stone tool)
    nounC2
  • Day-Lewis
    proper noun

Synonym discussion

Sense: noun/1

These three terms all describe types of acids, but they focus on different chemical mechanisms. A 'Lewis acid' is defined by its ability to accept a pair of electrons — it does not need to contain hydrogen. A 'Brønsted acid' (also called a proton donor) is defined by its ability to donate a hydrogen ion (H⁺); most everyday acids like lemon juice or vinegar are Brønsted acids. 'Electron-pair acceptor' is a fully descriptive term that explains what a Lewis acid does, but it is less common in textbooks. For example, boron trifluoride (BF₃) is a Lewis acid because it accepts an electron pair from ammonia, but it is NOT a Brønsted acid because it has no hydrogen to donate.

Lewis acidBrønsted acidelectron-pair acceptor

Etymology

FrankishOld FrenchEnglish

Both technical noun senses are named after people. The chemistry sense (Lewis acid) comes from the American physical chemist Gilbert N. Lewis (1875–1946), who proposed the electron-pair theory of acids and bases in 1923. The construction sense (the stone-lifting device) is also believed to be named after a person, though the exact historical figure — perhaps the inventor or first user of the mechanism — is no longer certain. The surname Lewis itself comes from the Old French name Louis, from the Frankish *Hludowig ('famous warrior').